An introduction to Molecules
Atoms are the building blocks of all living things on this planet. An atom is the smallest unit that makes up a chemical element. Atoms make up everything else that is solid, liquid, or gas. Atoms are made up of protons, neutrons, and electrons that are contained within the nucleus of an atom. What happens when two or more atoms collide? They combine to form molecules. Molecules are formed when two or more atoms form chemical bonds with one another. Understanding the properties and structure of atoms and molecules is not easy, but once understood, it is a fascinating subject to study.
What are Molecules?
Elements are created when the same types of atoms combine. The number of atoms that make up a molecule has the same ratio. The structure of elements determines their properties. Elements can be made up of one or more atoms. Take, for example, oxygen, which has two atoms (\({O_2}\)). Atoms are not depicted to scale. A compound is formed when these elements are combined. We can use \({H_2}O\) in this case. Water contains two hydrogen atoms and one oxygen atom. Similarly, larger chemical compounds such as methane (\(C{H_4}\)). We can learn from these how a group of atoms with a nucleus can form elements and compounds with various properties and structures.
What is the difference between Atoms and Molecules?
| Atoms | Molecules |
| Atoms are the smallest particle that can exist. | Two or more atoms combined to form molecules. |
| Atoms may not be stable due to the presence of electrons in the outer shells. | Molecules attain stability. |
| They contain protons, neutrons, and electrons. | Two or more atoms are formed and hence, they are strong. |
| Examples: Oxygen (O), phosphorus (P), sulphur (S) etc. | Examples: Oxygen (O2), water (H2O), and sulphur (S8). |
Summary
Elements can be single atoms, such as He, or elemental molecules, such as hydrogen (\({H_2}\)), oxygen (\({O_2}\)), chlorine (\(C{l_2}\)), ozone (\({O_3}\)), and sulphur (\({S_8}\)). Atoms are not depicted to scale. Some elements are monatomic, which means that their molecular form is made up of a single (mono-) atom (-atomic).
Frequently Asked Questions (FAQs)
1. What do you understand by the Law of Conservation of Mass?
Ans: According to this law, “Mass can neither be created nor destroyed.” This law can be applied to a chemical reaction in the following way:- During a chemical reaction, the total mass of reactants equals the total mass of products.
\[\left( {Reactant} \right){\rm{ }}A + B{\rm{ }} \to {\rm{ }}AB{\rm{ }}\left( {Product} \right)\]
2. What is an atom?
Ans. According to modern atomic theory, an atom is the smallest particle of an element that participates in a chemical reaction and retains its identity throughout the chemical or physical change.
3. What do you understand by the Law of Constant Proportion?
Ans. According to this law, “A pure chemical compound always contains the same elements combined in the same proportion by mass, irrespective of the fact from where the sample has been taken or from which procedure has it been produced.”