Category: Chemistry

Introduction

There is matter in our universe. The matter is anything that maintains a quantity and a space. These things have a fundamental unit that cannot be divided into other parts with various chemical and physical properties. An atom is this fundamental component. An element is a substance that only contains one type of atom. Therefore, the species made up of a specific atom are the elements. For instance, there is only one type of atom in pure platinum metal. The atom was once thought of as an indivisible unit, but now it can be divided, releasing a huge amount of energy in the process.

Define an Atom and Molecule

An atom is the tiniest component of matter. The physical and chemical characteristics of the atoms that make up an element are all the same type. An atom is mono-nuclear, meaning that it has just one nucleus, which is surrounded by electrons and houses protons inside the central mass of the atom, the nucleus.

Chemical bonds bind the minimum required number of atoms in a molecule together. It is the joining of various atoms with the assistance of a chemical bond. The molecule oxygen\(\;({O_2})\) is a diatomic homo nuclear structure made up of two oxygen atoms bound together by a covalent bond.

What is the size of an Atom?

Only an estimation of an atom’s size can be made because it is impossible to measure it precisely. However, an atom’s atomic radius determines its size. Atomic radius is calculated by dividing the distance between adjacent atoms in a compound by two. Radii come in a variety of forms, including metallic, covalent, and ionic radii. The metallic radius is the separation between adjacent atoms in a metal. The covalent radius is the separation between adjacent atoms in a covalent compound. Ionic radii are the distances between adjacent ions in an ionic compound.

How atoms are formed?

The atom is the smallest unit of matter, consisting of a nucleus and electrons. The nucleus is the central portion of the atom that contains the positively charged proton and neutral neutron. And is surrounded by electrons that are negatively charged. Protons, electrons, and neutrons make up an atom. They are collectively known as subatomic particles.

Forces between Atom and a Molecule

Molecules are formed when atoms are held together by a strong chemical bond. These bonds are formed by the interaction of an element’s valence electrons to complete the octet. Chemical bonds are classified into several types. They do,

1.Ionic bond: When two atoms approach each other and have a large electronegativity difference, electrons, and anion forms are accepted. And the one that lost an electron will become an anion. An Ionic bond is formed as a result of the attraction caused by the positive and negative charge.

2.Covalent bond: When atoms with similar electronegativity differences approach each other, they share electrons. And this is a covalent bond.

Summary

Chemistry’s fundamental terms are atoms and molecules. Atoms are the fundamental building blocks of elements. A molecule is formed by the combination of different atoms using a chemical bond. These bonds could be covalent or ionic. Protons, neutrons, and electrons make up an atom. The size of an atom cannot be calculated precisely; only an approximation of size is possible. 

Frequently Asked Questions 

1. What exactly are isotopes?

Ans. Isotopes are atoms with the same atomic number but different mass numbers. The same atomic number denotes the same number of protons. And a different mass number means a different neutron number.

2. What is the mass number?

Ans. The mass number is the sum of protons and neutrons added to an atom of a chemical element. Lithium, for example, has a mass number of 7. Lithium has 3 protons and 4 neutrons.

3. What is the chemical formula?

Ans. A molecular formula is an expression used to represent a chemical compound that is the simplest whole-number ratio of the composition of elements present in a molecule.

Introduction

Atomic orbitals are the three-dimensional spaces that surround the nucleus and are most likely to contain an electron. The atomic orbitals have been combined to create molecular orbitals. They obtain orbitals in quantum theory, some of which are electron shells in the s, p, d, and f configurations. Although orbitals come in a variety of shapes and sizes, their square can be used to estimate their size or even shape. A total of two, six, ten, or fourteen electrons could fit in the s, p, d, and f subshells, respectively. The particular arrangement of electrons within orbitals in such an atom determines the majority of the chemical compositions of that atom. Depending upon the energy over its electrons, every orbital class seems to have a distinct form. The s orbital has a spherical geometry. The p orbital has the form of a dumbbell, as well as 3p orbitals, which vary in their arrangement across a 3-dimensional axis.

Define Atomic Orbitals

Atomic orbitals are numerical values that provide additional details about the waveform of electrons that inevitably surround atom centers. In the fields of quantum systems and atomic theory, specific mathematical expressions are frequently employed to determine the likelihood of detecting an electron at even a specific area surrounding the nucleus of an atom. The term “atomic orbital” may also refer to the region above an atom’s nucleus where there is the greatest chance that a particular electron will become accessible. Several quantum numbers affect each atomic orbital’s characteristics:

Table of All Possible Atomic Orbitals, where the Value of ‘n’ Ranges from 0 to 5

What do you mean by Atomic Orbital Theory?

An atomic orbital is a statistical term that describes the location or even waveform behavior of such an electron in an atom in both atomic theory and quantum field theory. These electrons, each of which has a distinct spin quantum number s, can fit into any one of these orbitals up to a maximum of two. One such formula can be used to determine whether it is possible to find an electron inside the nucleus of any atom at any particular location.

Summary

Atomic orbitals seem to be the regions around the nucleus of an atom where electrons have often been observed at that particular time. This is a mathematical concept that characterizes the wave-like activity with 1-2 electrons in an atom. Electrons inhabit low-energy orbitals (near such nuclei) before electrons approach higher-energy orbitals. When there is an option of equal-energy orbitals, then occupy the orbitals freely as feasible. That filling of orbitals on its own is termed Hund’s law when applicable. Atomic orbitals are typically denoted by a series of digits as well as letters representing unique features of such electrons linked only with orbitals, including 1s, 2p, 3d, as well as 4f. Primary quantum numbers are values that further indicate levels of energy.

Frequently Asked Questions (FAQs)

1. Is it possible to have an orbital without an electron?

Ans. An orbital’s characteristics are more like the electron residing inside it. This is standard procedure, however irrational this could appear, to refer to ‘Empty orbitals.’ The characteristics of unoccupied orbitals are the same as those computed for electrons within them.

2. What is perhaps the greatest number of orbitals possible?

Ans. The values n=3 & l=1 indicate that it has been a 3p-orbital, however, the number \(f(m_{l}=0)\) indicates that it is indeed a \(3p_{z}\) in origin. As a result, the specified quantum number can only identify one orbital, namely 3p_z.

3. How do electrons fill orbitals?

Ans. According to the Aufbau principle, electrons first occupy lower-energy atomic orbitals before moving onto the higher ones. Based on this method, we may forecast the electronic structure of atoms and ions.

Introduction

While the number of protons is merely the atomic number, the atomic mass of an atom is the sum of both its protons and neutrons. The letters A and Z can be used to denote these. Since it offers the key to the element’s existence, the atomic number is the concept that deals with such a periodic table element. It is only after interacting with this particular proton, which is primarily referred to as this hydrogen isotope’s protium, that the atomic and mass numbers are the same. Keep in mind, in particular, that while the atomic number remains constant, the mass number could change due to the presence of multiple isotopes. The elements are arranged in numerical order by atomic number.

Define Atomic Number

The number of protons in the nucleus of an atom is the atomic number. This is denoted by the letter Z. The number of electrons that surround the nuclei is controlled by the number of protons. In a periodic table with ascending atomic numbers, compounds with similar chemical properties typically cluster in the same column. Different elements have distinctive atomic numbers. For example, all C atoms have an atomic number of sixes, whereas all O atoms have an atomic number of eights.

Define Mass Number

Rutherford proved that an atom’s nucleus, which is composed of protons and neutrons, contains perhaps the majority of the atom’s mass. The mass number refers to the total number of protons and neutrons in such an atom. Atomic mass units are used to measure this. To represent it, the letter “A” is frequently used. This has typically been accomplished by simultaneously adding both neutrons and protons.

For instance,\(Cl^{37}_{17} \) appears to have a mass number of 37. Its nucleus contains twenty neutrons and seventeen protons.

What is the difference between Valency, Atomic number and Mass number

Valency	Atomic Number	Mass Number
The greatest amount of electrons that even an atom could lose, gain, as well as share, in addition to getting stable is referred to as valency.	An atomic no. is the no. of protons that exist in such an atom.	The mass no. within an atom is the total of its protons as well as neutrons.
The electronic arrangement of such an atom could be used to evaluate its valency.	The mass number has always been less than the atomic no.	The atomic no. is always greater than that of the mass number.
The no. of atoms does not affect valency.	No. of neutrons in an atom does not impact its atomic no.	The no. of neutrons inside an atom seems to not affect the mass no.
The no. of electrons does have a direct relationship with valency.	The atomic no. of isotopes seems to be the same.	The mass number of isotopes varies.
Elements are classified as monovalence, divalence, and trivalence based on their valency.	Isobars with similar atomic no. cannot exist.	The mass no. of isobars would be the same.

Energy Levels of Atomic Orbital

When an electron reaches a certain energy level, it is more likely to be found in these regions than in other regions. Orbitals are the name for those sections. Orbitals with roughly similar energies have created sub-levels. The maximum capacity for each orbital is two electrons. The energy of such an electron in a specific atom may be determined solely by the primary quantum number. In order of increasing orbital energy are the following orbitals:

\(1s<2s=2p<3s=3p=3d<4s=4p=4d=4f\)

Summary

The mass number of an atom’s nucleus is an integer equal to the sum of the nucleus’ protons and neutrons. The atomic number, in contrast, is simply the number of protons. Even though their mass is so small compared to that of protons and neutrons, electrons are not counted when calculating mass because they have no impact on the value. The number of neutrons may change, even though the number of protons in such an element’s units remains constant. An electron appears to have very little mass. Therefore, an atom’s atomic mass is roughly equivalent to its mass no. The mass number represents the weight of an atom’s nucleus in atomic mass units.

Frequently Asked Questions (FAQs)

1. Is there a relationship between atomic mass and weight?

Ans: No, atomic mass is indeed the weight of an atom, while atomic weight denotes the weighted average of naturally produced elements.

2. Why does an atomic number refer to as a fingerprint?

Ans: The physical or chemical characteristics of an atom have been exclusively governed by the no. of electrons inside its nucleus, but often along with its nuclear charge: the nuclear charge would be an element’s specific “fingerprint,” as well as Z identifies the chemical components individually.

3. Why is it that a mass number is typically a whole number?

Ans: Since it is the total number of the particles, the mass no. is always a whole number. This varies from the atomic mass unit, which is well recognized, as well as written to 6 decimal points.

Introduction

In 1913, Neil Bohr introduced the Atomic Model, which was based on Planck’s quantum theory of radiation. In overcoming the limitations of Rutherford’s atomic model and describing the hydrogen spectral lines. One such model appeared to be very effective in describing the atom’s stability, as well as the line spectra of an H atom. This model hypothesis correctly predicted smaller atoms such as hydrogen, but when larger atoms were observed, poor phantom assertions were made. However, it does not describe the Zeeman effect, atomic spectra, the Stark effect, or Heisenberg’s Uncertainty Principle.

An Overview of the Bohr Atomic Model

According to Bohr’s Atomic Model, an atom is made up of a tiny, positively charged nucleus surrounded by electrons that move in circular orbits all over the nucleus, attracted by electrostatic forces. He was also awarded the Nobel Prize in Physics for his contributions to atomic structure.

The Bohr Atomic Model’s Postulates

1. Orbits are allowable circular trajectories in that electrons travel all over the nucleus.

2. Because each orbit was associated with a specific amount of energy, they were referred to as energy levels and energy states.

3. Shells of energy have been labelled as 1, 2, 3, 4,… or even K, L, M, N…., and so on. The energy level closest to the nucleus is denoted 1 and is known as the K shell.

4. When travelling at a certain energy level, an electron does not lose or gain energy. In such a given energy state, an electron’s energy appears to be fixed as well as stationary. This is referred to as the normal or ground state.

5. When an electron moves from one orbit to the next, it both emits and absorbs energy. When it travels from a higher energy state to a lower energy state, it releases energy, and when it travels from a lower energy state, it consumes energy.

6. Planck’s equation calculates the absorbed and released energy as the difference between the energies of the energy states.

Bohr’s Atomic Model’s Limitations

1. Bohr’s concept did not explain the atomic spectrum of elements with more than one electron.

2. This does not account for the Zeeman effect, which occurs when a magnetic field breaks spectral lines into densely closed lines.

3. It also fails to illustrate the Stark effect, which occurs whenever spectral lines are broken into fine lines by an electric field.

4. According to Bohr, electrons’ circular orbits appear to be flat. However, a new study shows that an electron travels in 3 dimensions across the nucleus. Because light electrons have a dual nature, this would be centred on de Broglie’s idea.

5. Bohr’s atomic model would not adhere to Heisenberg’s uncertainty principle. According to this theory, determining the precise position and momentum of a tiny circulating particle like an electron with extreme certainty appears to be difficult. As a result, electrons follow a well-defined circular path.

6. Bohr’s hypothesis can never explain the shapes or the structure of molecules. This incorrectly considered large-sized atoms while providing sufficient information about smaller atoms.

Summary

Niels Bohr’s atomic theory includes definite-size electrons as well as energies travelling in orbits around a central nucleus, similar to how planets orbit the sun. To summarise Bohr’s atomic model, the energy states of electrons are focused on the size of such orbits. As a result, electrons in tighter orbits would have less energy. Atoms are unstable because electrons move to drive down orbits, resulting in radiation. Because the electron appears to have no lower orbit to which it can jump, an atom within the smallest orbit has now become completely stable. As a result, it was hypothesised that such an electron could move between these orbits by absorbing and losing photons.

Frequently Asked Questions

1. What exactly is the Bohr Atomic Model Theory?

Ans. Bohr was the first to discover not only that electrons revolve around the nucleus in distinct orbits, but also that the total number of electrons in an element’s outermost shell can be used to define its properties.

2. What is preventing atoms from collapsing?

Ans. The electrons of an atom are kept from collapsing within the nucleus by balancing kinetic and potential energy.

3. What is the radius of a Bohr orbit?

Ans. The Bohr radius, denoted by ‘r,’ has been defined as the mean radius of an electron’s orbit around the nucleus of an H atom in its initial state. Its radius has become a standard value, roughly equivalent to \({5.2917710^{ – 11}}m.\).

Introduction

Calcination and roasting are two processes used to convert ores into oxides. Ores are a naturally occurring substance found in the earth’s crust. These ores are rich in minerals and valuable metals. Metals extracted from ore are required by applying lots of heat, either in the presence or absence of oxygen. Processes such as calcination and roasting are used to convert ores to oxides. The following is a step-by-step diagram for converting ores to oxide and extracting pure metals.

To produce oxide, raw ore is required. During this process of conversion, it expels volatile substances and gas. The removal of volatile impurities in solids and gases results in the extraction of metals from ores’ oxides. Furthermore, electrolytic refining purifies metal.

What Exactly is Calcination?

It is the process of converting carbonate ore to oxide below its melting point using heat in the absence of air or with a limited supply of oxygen. It is also referred to as the thermal decomposition process because it decomposes ore or solid substances without changing their chemical properties and only removes volatile and organic impurities. As an example:

\[ZnC{O_3} \to {\rm{ }}ZnO{\rm{ }} + {\rm{ }}C{O_2}\]

How would you define Calcination?

Calcination is a thermal or heat process that occurs when a solid substance, such as carbonate ore, is heated above its melting point in the absence or limited supply of oxygen. Calcination is derived from the Latin word Calcinare, which means ‘to burn lime’. As a result, the most commonly used ore limestone (calcium carbonates) produces quicklime in the absence of air or oxygen at temperatures ranging from 900 to 1050 °C (calcium oxide). The following is my reaction:

\[CaC{O_3} \to {\rm{ }}CaO{\rm{ }} + {\rm{ }}C{O_2}\]

Why Calcination is Necessary

Calcination is a method of purifying ores. Heating ores or solids to temperatures well below their melting points causes the decomposition or removal of volatile impurities, moisture and water, and organic matter. As an example:

1. Carbon dioxide removal from carbonated ores.

2. Hydrated molecules are extracted from bauxite and gypsum. The following is the reaction:

\[A{l_2}S{O_3}.2{H_2}O{\rm{ }} \to {\rm{ }}A{l_2}{O_3} + {\rm{ }}2{H_2}O\]

1. The extraction of volatile liquids from petroleum and coke.

2. In the preparation of zeolites, ammonium ions are removed.

What Exactly is Roasting?

It is a process of converting mainly sulphide ores into their respective metal oxides when subjected to heat in the presence of air or oxygen. It is one of the metallurgical processes.

How would you define Roasting?

The heating process of converting sulphide ores into metal oxides below their melting point in the presence of air or oxygen is known as roasting. The conversion of ore into oxides alters the chemical properties of the solid ores and results in the formation of a new product after impurities are removed. The roasting of zinc sulphide into zinc oxide results in the following reaction:

\[2ZnS{\rm{ }} + {\rm{ }}3{O_2} \to {\rm{ }}2ZnO{\rm{ }} + {\rm{ }}3S{O_2}\]

Why Roasting is Necessary?

Roasting is a process that converts sulphide ores into oxides by heating them to high temperatures in the presence of oxygen. It is used in the metallurgy process to extract metals or their oxides from ores by removing metallic, non-metallic, toxic, and moisture impurities in the form of volatile substances. The following impurities are removed during conversion:

1. Sulphur removal from sulphide ores.

2. Phosphorus and silicon in flux are removed. Flux is used to remove impurities in the form of slag.

What are the Main Differences between Calcination and Roasting

Calcination	Roasting
In the absence or limited supply of oxygen or air, the ore is heated.	Heat is applied to ore in the presence of an excess of oxygen or air.
Carbonate ores are processed using this method.	This method is employed for sulphide ores.
Only decomposition occurs in this process, and oxygen is not involved in the reaction.	Oxygen is reacted with sulphide ores in this process.
Impurities such as organic matter and water are expelled.	Toxic impurities are removed.
Carbon dioxide is produced along with metal oxide.	Metal oxide and sulphur dioxide are both produced.
The process is also carried out in a reverberatory furnace. The furnace’s holes were kept closed.	It is accomplished in a reverberatory furnace. The holes in the furnace were kept open to allow oxygen or air to enter.

Summary

Metals can be extracted using roasting and calcination processes. Metal-containing ores and minerals are not always present in the oxide form; in this case, roasting and calcination processes are used. Both processes convert the ore to its oxide form. This facilitates the extraction process. These only change when exposed to high temperatures. However, roasting occurs in the presence of oxygen, whereas calcination occurs in the absence of oxygen. During thermal decomposition, roasting produces new products, whereas calcination decomposes the solid substance. Both produce metal oxides, which can then be reduced to metals.

Frequently Asked Questions

1. Is there a physical process involved in calcination?

Ans. It is a decomposition process in which solid substances are broken down when high heat is applied. During this process, no new products are formed. As a result, it is only a physical change or process.

2. How do the calcination reactions take place?

Ans. Calcination reactions occur in retorts and furnaces. The ores or solid substances are stirred in this process to produce a uniform product.

3. Why are roasting and calcination done at temperatures below the melting point?

Ans. If ores are heated above their melting point, they will melt and mix with difficult-to-separate carbonate and sulphur impurities.

Introduction

We use a variety of materials for our necessities. Some are naturally occurring, while others are the result of human labour. Natural resources are plentiful as a result of the abundance of numerous resources in nature. Carbonization contributes significantly to global coal production. Coke is the primary by-product of high-temperature carbonization; approximately 4% of the total input coal is converted into tar and crude benzol (light oil), with significant amounts of gas also produced. The following useful products are produced by processing coal without the use of air:

1. Coal and Gas

2. Coke

3. Tar from coal

Coal and Gas

Coal gas is a combustible vapour fuel extracted from coal that is piped to customers. Town gas is a broader term for gaseous fuels produced for commercial sale and community use. In some places, it is also known as manufactured gas, syngas, or producer gas.

Depending on the techniques used to create it, coal gas is a mixture of gases such as, and, as well as volatile hydrocarbons, with minor quantities of non-caloric gases such as and as impurities.

In the nineteenth century, coal gas, which was primarily a by-product of the cooking process, was widely used for lighting, cooking, and heating. The rise in natural gas production coincided with industrialization and urbanisation, and the by-products, coal tars and ammonia, served as key chemical feedstock for the chemical industry.

Coal, oil, and gas production

Coal gas is produced when coal is heated in an enclosed chamber with no air.

When bituminous coal is heated to 400 °C, it relaxes and coalesces, releasing water steam, rich gas, and tar. Crude oil, coal, and gas are examples of fossil fuels. Over centuries, coal oil was produced from the remains of dead trees and other plant debris. Crude oil and natural gas were extracted from dead sea creatures.

Composition of Coal gas

Coal gas is a gaseous mixture of \({H_2}\), CO, and \({H_4}\) that is produced and used as fuel by destructive distillation (burning bituminous coal in an inert atmosphere). Steam is occasionally introduced to combine with the heated coke, increasing gas production. It is primarily composed of \({H_2}\) and \({H_4}\), with trace amounts of other hydrocarbons, carbon monoxide (a lethal gas), carbon dioxide, and nitrogen. It functions as both a fuel and an illuminant.

Uses of Coal

Coal is used for a variety of things, including

1. Electricity generation: Coal is primarily used to generate electricity. When thermal coal is burned, steam is produced, which powers turbines and generators that generate energy.

2. Liquification, as well as Gasification, is the process by which coal is burned and crushed with steam to produce town gas for home heating and lighting. It is liquefied to produce synthetic fuels that are similar to petrol and diesel.

3. Chemical, as well as other industries: Syngas can be used to create chemicals such as methanol and urea. Coal is widely used in the paper, textile, and glass industries. Coal is also used to make carbon fibre and other speciality components such as silicon metals.

Define Coke and State its Properties

Coal is distilled destructively to produce a high-carbon product. Coke is known as a virtually pure form of carbon due to its high carbon concentration. It’s a greyish-black solid that’s hard and porous. It is used as a reducing agent and a fuel in mineral extraction and steel production.

1. It has nearly pure carbon properties.

2. It is hard, porous, and black.

3. When it burns, it produces no smoke.

Uses of Coke

1. In metal extraction, it is used as a reducing agent.

2. Used in the steelmaking process.

3. It can also be used to generate energy.

Define Coal Tar and State its Properties

Coal Tar is a by-product of the coke manufacturing process. It has the same colour as coke, but it is a thick, viscous liquid with a foul odour. It is used to make synthetic colours, pharmaceuticals, fragrances, plastics, paints, and other products. Not only that, but it is also capable of producing naphthalene balls.

Coal tar was discovered in 1665 and used for medicinal purposes in the 1800s. Itchy skin, UV sensitivity, allergic reactions, and skin discolouration are all potential side effects. It’s unclear whether taking it during pregnancy is safe for the baby, and it’s not usually recommended to take it while breastfeeding.

Coal Tar Applications

Coal tar is primarily used to produce coal-tar products, as well as refined chemicals such as coal-tar pitch and creosote. Coal tar treatments have long been used to treat skin conditions such as eczema and dandruff.

Summary

Coal, as a solid carbon-rich material that is black/brown and occurs in stacked sedimentary layers, is one of the most important fossil fuels. In the future, coal liquefaction techniques could provide readily available, non-polluting fuels and chemical raw materials. Analytical criteria play a significant role in the four coal refining processes described above. Fumes, oils, and tars, as well as soluble but low-volatile extracts, pitches, and cokes, must all be investigated.

Frequently Asked Questions

1. Why do fossil fuels pollute the atmosphere?

Ans. The combustion of fossil fuels produces significant amounts of air pollution and pollutants such as \({H_2}\), CO, and \(S{O_2}\), all of which can contribute to climate change by increasing the greenhouse effect.

2. What exactly is petroleum?

Ans. Petrol, plastic, and other chemical compounds are derived from petroleum, a mineral oil found beneath the ground or in the sea. Petroleum by-products include wax, kerosene, LPG, petrol, lubricating oil, and diesel.

3. What are the different types of coal?

Ans. The least valuable and softest type of coal, with the lowest carbon concentration, is peat. Because of its high moisture content, it is unsuitable for use as fuel.

Anthracite coal is the best available. This type of coal is also known as hard coal. It contains the most carbon. It only produces a small amount of smoke.

Lignite is slightly firmer than peat, but it is still quite soft. It contains more carbon than peat.

Introduction

The distance between the nucleus’s core and the valence shell/outermost shell, known as the atomic radius of an element, serves as a benchmark for the size of its atom. The periodic table shows that the atomic size increases as you move down it and decreases as you move from left to right. The reason for this is that as you move down the group, the number of shells increases, the screening effect multiplies, and the force of attraction weakens, causing the atomic radius to increase. Additionally, the nucleus’ protons increase as you move from left to right, drawing electrons in and shrinking the atomic radius in the process.

Basic understanding of Atomic Radius

The atomic radius is typically defined as the total distance from an atom’s nucleus to its outermost electron orbital. It can be expressed more simply as something resembling a circle’s radius, with the nucleus serving as the circle’s centre and the electron’s furthest orbital serving as the circle’s edge.

What Are the Trends in Atomic Radius? Why Do They Occur?

There are two main trends in atomic radius. One atomic radius trend appears as you move across the periodic table from left to right (doing so within a period), and the other trend appears as you move from the periodic table’s top-down (moving within a group). To help you comprehend and visualise each atomic radius trend, the periodic table below includes arrows that show how atomic radii change.

1. Atomic Radius Trend 1: Atomic Radii Decrease From Left to Right Across a Period

The first atomic radius periodic trend is that as you move from left to right across a period, atomic size decreases. Each additional electron is added to the same shell within a group of elements. A new proton is also added to the nucleus when an electron is added, increasing the nuclear attraction and boosting the positive charge of the nucleus.

In other words, as protons are added, the nucleus gains a stronger positive charge, which in turn attracts the electrons more strongly and draws them in toward the nucleus of the atom. The radius of the atom decreases as the electrons are drawn inward toward the nucleus.

2. Atomic Radius Trend 2: Atomic Radii Increase as You Move Down a Group

Atomic radii rise as you descend in a group in the periodic table, which is the second atomic radius periodic trend. The atom gains an additional electron shell for every group down. The atomic radius grows as each new shell is positioned farther from the atom’s nucleus.

Contrary to popular belief, electron shielding keeps the valence electrons from the nucleus (those in the outermost shell). The electron shielding effect, which occurs when an atom has more than one electron shell, reduces the attraction of the outer electrons to the atom’s nucleus. As a result, electron shielding prevents the valence electrons from getting very close to the atom’s centre, increasing the atom’s radius.

Summary

Atomic radius is characterised by two major trends. The first periodic trend in atomic radii is the increase in atomic radius with decreasing group size. Electron shielding is the cause of this. When a new shell is added, the atomic radius grows as a result of the new electrons’ increased distance from the atom’s nucleus. More protons give an atom a stronger positive charge, which attracts electrons more strongly and pulls them toward the nucleus, shrinking the size of the atom. According to the second atomic radius periodic trend, atomic size decreases from left to right across the period.

Frequently Asked Questions

1. The atomic radius of which of the atoms-Arsenic or Selenium, is the largest?

Ans. Arsenic has a larger atomic radius than Selenium. The reason for this is that the extra protons increase the positive charge in the nucleus, which pulls the electrons closer together, reducing the radius. Arsenic along with Selenium is on the bottom row of the possibilities, but Arsenic is to the left. As a result, its atomic radius is the greatest.

2. What is the atomic radius of F and Ne in Angstrom?

Ans. The atomic radius of F and Ne in Angstrom is 0.72, 1.60. Noble gas elements quoted radii are “van der Waals radii,” which are 40 percent larger than their true atomic radii. As a result, the atomic radius of neon must be substantially larger than that of F. 

3. Is it the size of Ne or \({\bf{N}}{{\bf{a}}^ + }\) that is smaller? Why?

Ans. \(N{a^ + }\) = proton number = 10

Ne = proton number = 10

Both are isoelectronic species, meaning they have the same number of electrons and shells (10 electrons). The size will be determined by the number of protons and nuclear charge. Because the sodium ion has 11 protons, the higher the nuclear charge, the stronger the nucleus’ affinity to valence shell electrons, and the size shrinks. The size of \(N{a^ + }\) is smaller than that of Ne.

Introduction

Coal appears to be a dense carbon-rich substance that is brown/black and formed in layered sedimentary rock. This is one of the most important major fossil fuels. It is said to contain half of the total carbon-containing substance by weight generated by the compression and stiffening of modified plant residues, primarily peat settlements. Because of differences in plant matter, the extent of coalification, and the impurity spectrum, there are many types of coal. French explorers and fur traders discovered North American coal seams near the coast of Grand Lake in southern New Brunswick, Canada, in the 1600s. Coal deposits were discovered wherever rivers flowed deeper into the lake, but they were also excavated by hand from the surface, and caves cut into the rock. Coal is not the most abundant fossil fuel, but it has the longest history.

What do you understand by coal?

Coal appears to be a shiny black rock. Coal contains a tremendous amount of energy. When coal is burned, it emits both heat and light energy. The cave dwellers used coal for warmth, but ultimately for cooking. It could have been very simple to burn because it worked better than wood and did not need to be retrieved as frequently. People began using coal to heat their homes in the 1800s. Coal was used as a fuel source for both trains and ships. Nowadays, coal is primarily used to generate electricity. The four primary types or grades of coal are peat, anthracite, lignite, and bituminous coal.

What is the Coal Story?

As they died, the plants sank to the bottom of the wetlands. Throughout the years, excessive amounts of vegetation have been coated in dirt and water. They had been compressed by the weight. The heat and pressure eventually converted these plants into coal. Because coal is produced by plants, and plants obtain their energy from the sun, the power in coal is also derived from the sun. Coal, as we know it today, formed over millions of years. We can’t even produce that much in such a short amount of time. This is why coal is considered non-renewable.

How is Coal Obtained

• This is derived from beneath deposits that are either ores coatings or are large enough to be extracted profitably.
• Mining could be done in one of two ways: underground or open pit. The type of extraction is determined by the overall depth of such a deposit.
• Vertical tunnels are used to access resources, whereas surface and open-pit mining remove dirt and rocks on top of mineral reserves.
• Surface mining costs less than underground mining. As a result, surface mining is much more common.

Also Read: Coal Formation Stages

Uses of Coal

• Coal is now used not only as a cooking fuel but also as a heat source, particularly in cold climates and developing countries. This provides a much cheaper method of cooking as well as heat production in areas where liquified petroleum gas and Biogas are not available.
• It is frequently used as a basic component in the production of everyday commodities such as steel and iron. Coal has been used indirectly to produce steel in the steel industry.
• It is used in a variety of industries to manufacture a wide range of products. Coal is used in a variety of industries, including cement production, paper manufacturing, chemical manufacturing, and pharmaceutical manufacturing. Coal is used by the chemical industry to produce a variety of raw materials such as benzol and sulphate of sodium.
• Coal is used to make carbon fibre. It is the strongest and lightest element available for making stabilisers, sports equipment, and even mountain motorcycles.
• It aids in the development of alumina mills.
• Likewise, it could have been converted into gas or liquid, which could have been used to power vehicles such as automobiles, motorcycles, and ships.
• Furthermore, it is primarily used as fuel in the combustion process to generate energy. Thermal coal is frequently used to generate energy in power plants.
• Activated carbon is made from coal. Activated carbon is used in air and water purification filters, as well as renal dialysis technology.
• Activated charcoal has been used in the production of cosmetics and facial treatments.

Summary

Coal, a carbon-rich substance that is usually black or brown, is found in multilayered rock deposits. This is one of the most important fossil fuels and can be found all over the world. For thousands of years, heat, and pressure on flora accumulated in old swampy wetlands have produced coal. Its volume, thickness, rigidity, and density all vary. It is constantly used as a fuel, an ash source, and a producer of various chemicals used in the synthesis of dyes, lubricants, and pharmaceuticals. Exploration for alternative energy sources has occasionally refocused attention on the processing of coal into liquid fuels; coal liquefaction methods were also recognised in the early twentieth century.

Frequently Asked Questions

1. What is coal’s environmental impact?

Ans. Particulate pollutants, ozone in the earth’s crust, acid rain, and smog are all environmental drawbacks of using coal as a source of energy. Fly ash granules are released into the atmosphere after coal is burned with fuel oil, causing air pollution problems.

2. What exactly is the coal formula?

Ans. The four types of coal are anthracite, bituminous, sub-bituminous, and lignite. The chemical investigation yields an empirical formula for bituminous coal, such as \({C_{137}}{H_{97}}{O_9}NS\), as well as anthracite, \({C_{240}}{H_{90}}{O_4}NS\).

3. What contaminants are present in coal?

Ans. Impurities such as sulphur and nitrogen have been discovered in coal. When coal burns, such pollutants are emitted into the atmosphere.

Introduction

Forests are essential to human life due to the diverse materials they provide. They produce oxygen, which is required for life on Earth, act as a carbon sink, and store carbon, earning them the moniker “earth lung.” Furthermore, they regulate the hydrological cycle and the global climate; purify water; provide habitat for wildlife, reduce global warming, absorb harmful gases, and perform numerous other functions. More trees are planted, and wooded areas are maintained through forest conservation to ensure their sustainability for future generations. But it has become crucial to protect forests around the world due to rising deforestation operations. Deforestation is the permanent removal or destruction of forests to make way for new agricultural, livestock, or other uses of the land.

Some reasons why forests are essential to our survival.

The sustainable production of wood and timber products, as well as the provision of food, housing, and energy, is one of the most important functions of forests. They provide critical ecosystem services for human well-being, such as-

1. Forests cover one-third of the Earth’s land area. They carry out critical tasks all over the world.

2. The forest absorbs damaging greenhouse gases that lead to climate change.

3. Forests provide clean water for drinking, bathing, and other household needs. They help to maintain the balance of oxygen, carbon dioxide, and humidity in the atmosphere.

4. Forests provide numerous environmental, economic, social, and health benefits.

5. Forest is distributing food and medication. Forests provide safety, employment, and housing for communities that rely on them.

6. Forest cover mitigates floods and other natural disasters.

7. Forests are critical in our efforts to adapt to and mitigate climate change.

8. More than half of the world’s land-based species live in forests. Woods have the most biologically diverse ecosystems on land.

9. Many of the disease-treating medications sold around the world are made directly from plants found in rainforests.

10. Forests produce rubber, lac, organic pigments, gum, resins, and other materials.

Forest conservation

Forest conservation does not imply that users should be denied access, but rather that access should be granted in a way that does not harm the environment or our economy. The following methods might be applied to preserve forests, which would eventually enhance forested areas and ensure the sustainability of the available resources:

1. Afforestation is the practice of planting trees for monetary gain. Instead of removing trees from naturally existing forests, a practice known as “afforestation” is used to establish them and use them as resources.

2. Forest fire suppression: Forest fires are the most common and lethal cause of forest loss. As a result, precautions must be taken in such cases. Making fire lanes, using fire-fighting chemicals, removing dead trees and dry leaves, and so on.

3. Addressing the root causes of deforestation: If we are to effectively expand the role of forests in providing for basic human needs, we must address the root causes of deforestation, such as poverty and the need for food, shelter, and fuel.

4. Verifying forest clearances for urbanization: In an era of rapid urbanization and industrialization, it is common practice to remove forests through encroachment or authorization. As a result, strict regulations should be put in place to prevent the urbanization of forest areas.

5. Examining the forest harvesting procedure: To ensure successful in-situ conservation of biological diversity during forest exploitation, current forest harvesting procedures should be critically evaluated by the provisions of the Convention on Biological Diversity.

How can we protect wildlife?

Wildlife conservation refers to the process of protecting plant and animal species as well as their habitats. Wildlife conservation is a response to the century’s steadily increasing rate of extinction. Humans are to blame for the current rate of species extinction. However, we remain optimistic that we can save our species by taking a few critical steps. These are

1. Speak up for wildlife: your voice matters! Encourage your state and federal representatives to support wildlife protection legislation in writing.

2. Planting native plants is a great way to make our yards more wildlife-friendly. This provides food, shelter, and a place for wild animals to raise their families.

3. Ecosystem protection: One of the simplest and most effective ways to help wildlife is to preserve the environment in which it lives. The three major environmental conservation methods are to reduce, reuse, and recycle.

4. Be an informed consumer: Avoid using items that endanger wildlife and their habitats, such as non-recycled paper products, gas-guzzling cars, and so on.

5. Preserving endangered species: The Endangered Species Act has proven to be a successful safety net for threatened species, saving more than 98 percent of the animals it has cared for from extinction.

What if all the forests are destroyed?

It is impossible to imagine our existence without forests. The following are some consequences of destroying the entire forest:

1. The amount of  in the \(C{O_2}\) atmosphere will increase. As a result, the Earth’s temperature will rise.

2. Many animals and plants are losing their natural habitats. If they cannot find a suitable environment to live in, they may eventually die or become extinct.

3. The soil dries out without trees, and the water cycle is disrupted. Rain will cause flooding because the land cannot hold the water.

4. We will not receive valuable forest products. Tribal members may also lose their source of income.

Summary

More trees are planted, and wooded areas are maintained through forest conservation to ensure the sustainability of wooded regions for future generations. We can rely on forests for shelter, work, water, food, and fuel security, among other things. The practice of preserving plant and animal species, as well as their habitats, is known as wildlife conservation. We, humans, have a responsibility to protect our species by taking a few key actions.

Frequently Asked Questions

1. What are the negative consequences of deforestation?

Ans. In addition to harming the environment, society, and especially the climate, biodiversity, and poverty, deforestation has a negative economic impact.

2. What exactly is the Global Forest Carbon Mechanism (GFCM)?

Ans. The Global Forest Carbon Mechanism is a financial structure that would reward developing countries for reducing their emissions.

3. How can we ensure food security while also halting deforestation?

Ans. The increased agricultural output should be achieved without cutting down more trees. Better land design and significant investment are required to increase yields on existing farmland.

Introduction

Old chemical bonds are cleaved in a chemical reaction and form new bonds. Any chemical equation should be balanced properly. It means the number of each atom should be the same on both the reactant and product sides. It is based on two rules; the ‘law of conservation of masses’ and the ‘law of constant proportions’. If a reaction is considered to be \(X + Y{\rm{ }} \to {\rm{ }}Z + P\), then X, Y are called reactants, and Z, P are called products of this reaction.

Define the law of conservation of mass.

It is stated in this law: “The mass in an isolated system can neither be created nor be destroyed but can be transformed from one form to another”. So the number of each type of atom in a chemical equation is always the same on both sides of the equation.
Read More: Law of Conservation of Mass with Experimental

Define the law of constant proportions.

The law states that- “In a chemical substance, the elements are always present in definite proportions by mass”. In the \({H_2}O\) molecule, the molar mass of two H atoms is 2 gm/mole and the molar mass of one O atom is 16 gm/mole. So their ratio of mass is 2:16=1:8. This ratio in \({H_2}O\) is always constant.

What is a balanced chemical equation?

According to the two laws of conservation of mass and conservation of definite proportions, a chemical equation must be properly balanced. It means that the number of all the atoms or molecules involved in a chemical reaction must be the same on both the reactant and product side. This is known as a balanced chemical equation. 

Importance of coefficients and subscripts in balancing a chemical equation

Coefficients are numbers that help us to determine the number of each atom present in a balanced chemical equation. It can be changed necessarily.

Subscripts are the numbers that help to determine the chemical formula of any compound. The subscripts are always constant throughout a chemical equation.

\[{N_2} + {\rm{ }}3{\rm{ }}{H_2} \to {\rm{ }}2{\rm{ }}N{H_3}\]

Method of generating a balanced chemical equation- 

Suppose we are trying to balance this unbalanced chemical equation. 

\[C{H_4} + {O_2} \to {\rm{ }}C{O_2} + {H_2}O\]

These are the steps that are followed to make a balanced chemical equation. 

• At first, the number of each atom on both sides is determined.

Atoms present	Number of atoms on the reactants side	Number of atoms on the products side
C	1	1
O	2	3
H	4	2

• Then coefficients of each atom are balanced properly. For this equation, at first, the coefficients of H are balanced. So now the chemical equation transforms into- 

\[C{H_4} + {O_2} \to {\rm{ }}C{O_2} + 2{\rm{ }}{H_2}O\]

• Now the coefficient of O is balanced accordingly. So the new chemical equation is:

\[C{H_4} + 2{O_2} \to {\rm{ }}C{O_2} + 2{H_2}O\]

This is the balanced chemical equation: \(C{H_4} + 2{O_2} \to {\rm{ }}C{O_2} + 2{H_2}O\)

Balancing the chemical equation- 

\[{C_3}{H_8} + {O_2} \to {\rm{ }}C{O_2} + {H_2}O\]

• At first, the number of each atom on both sides is determined.

Atoms present	Number of atoms on the reactants side	Number of atoms on the products side
C	3	1
O	2	3
H	8	2

• Now the coefficient of C is balanced on both sides. So the chemical equation changes to-

\[{C_3}{H_8} + {O_2} \to {\rm{ }}3C{O_2} + {H_2}O\]

After equating the coefficients of H, the new equation is:

\[{C_3}{H_8} + {O_2} \to {\rm{ }}3C{O_2} + 4{H_2}O\]

• Then the coefficients of O are balanced accordingly to form a balanced chemical equation.

\[{C_3}{H_8} + 5{O_2} \to {\rm{ }}3C{O_2} + 4{H_2}O\]

This is the balanced chemical equation: \({C_3}{H_8} + 5{O_2} \to {\rm{ }}3C{O_2} + 4{H_2}O\)

In this way, any chemical equation can be balanced.

Summary

According to the laws of conservation of mass and conservation of constant proportions, any chemical equation should be balanced properly. This is done by equating the coefficients of each atom involved in a chemical reaction. Balancing a chemical equation is extremely important in the field of chemistry. Based on the coefficients present before the molecules involved in a chemical equation, the yield of the products of that reaction can be determined.                                         

Frequently Asked Questions

1. State the limitations of using chemical equations.

Ans: By any chemical equation we can’t understand the states(solid/liquid/gas) of the compounds involved. Again, the reversibility or irreversibility of any reaction can’t be determined by the chemical equation. 

2. What are the different types of chemical equations?

Ans: Depending on the nature of reactants and products in a reaction, it may be classified into five types. They are combination reaction, single replacement reaction, decomposition reaction, combustion reaction, and double replacement reaction. Some reactions fall under two categories simultaneously. 

3. What is the main reason behind a chemical reaction?

Ans: A chemical reaction can be described as a bond-breaking and bond-making process. It means all the old bonds are cleaved and new bonds are formed. The molecules which react in a chemical reaction are called reactants and the molecules produced in a reaction are called products.