Tag: Period

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

The Upanishads were written between 700 and 400 BCE  in the Sanskrit language. They contributed to the ancient people’s advancement in spiritual understanding. Vedanta also known as the Upanishads means “end of the Vedic period”. There are roughly 200 Upanishads, the most famous of which are the Aitareya Upanishad, Brhadaranyaka Upanishad, Chandogya Upanishad, Isha Upanishad, Katha Upanishad, Kausitaki Upanishad, Kena Upanishad, Maitri Upanishad, Mandukya Upanishad, Mundaka Upanishad, Prashna Upanishad, Sveta.

Birth of Upanishads

The Vedas could only be read and translated by Brahmins, regular people had great difficulty understanding them. Saints, therefore, wrote a summarized version of the Vedas that included additional queries and concepts in the form of Upanishads. The Upanishads were written at a time when there was a great deal of social, political, and economic unrest. The rural tribal civilization was in danger of extinction because the monarchy absorbed the people into urban life. In times of uncertainty, learnings from the Upanishads gave people peace, a sense of self-realization, and purpose.

Upanishads and Indian Society

The Upanishads are the repository of Hindu philosophy, and they served to uplift and maintain Hindus for a long period. Combining various Upanishads will give a good picture of the kind of civilization and way of life that existed during that era. 

At that time, the kings were specialists in both administration and warfare. They made an effort to promote knowledge of Vedic religion and also provided sanctuary for wise men and sages. 

The Upanishad era was characterized by a strong caste system. In terms of the Ashram system. Brahmacharya, Garhasthya, and Vanaprastha were more prevalent, while Sannyasa may also have been practised. The sanctity and integrity of each person’s private life were emphasized.

The status of women in Hindu society during that era was relatively high. During this time, females participated in spiritual discussions. Gargi and Maitreyi were famous women who participated in such discussions and gave their views regarding various spiritual topics. 

Learnings from Upanishads

The Upanishads are thought to be the authentic teachings of the sages of ancient India.

Learnings from the Upanishads include:

• The philosophy of human spiritual realization, including the meaning of life, existence, birth, and death, is addressed in the Upanishads.
• It explained the complicated truth of existence and how a  person can correct his thinking and be inspired to think differently from the inner soul’s perspective.
• It enabled people to examine their beliefs and give their relationships more meaning.
• The Upanishads describe the understanding of Brahman and Atman’s self-existence. Atman is a particular soul, while Brahman is the all-pervading soul.
• People learned about their being and how Brahman and Atman combined formed the substance of “permanence” (which existed) through the Upanishads.
• The four doctrines of dharma, karma, samsara and moksha are the foundation of the Upanishads and are well explained in these texts.
• According to the Upanishads, a spiritually aspirational person must think about the symbolic sacrifices that occur in the mind rather than concentrating on external sacrifices.
• Last but not least, the Upanishads explain the self-realization theory. By realizing the purpose of life, people might lessen their sorrow and suffering.

Interesting Facts 

• The best place to learn about self-realization and life’s realities is from the Upanishads.
• The impact of the Upanishads was not limited to India; it also extended to other nations.
• Although there are about 200 Upanishads, the majority of Hindu literature only mentions 108 of them.
• These Upanishads were among the earliest intellectual writings ever discovered; they even predated the Bible and the Qur’an by 800 and 1300 years, respectively.
• The Upanishads claim that Hindu sages united several Gods because they believed in unity. 
• Agni, Indra, and other Vedic deities are compared to the highest truth and given a spiritual purpose.
• The development of various Vedanta that differed from the Brahman and Atman aspects was aided by the Upanishads.

Summary 

The most important learning from the Upanishads-The final triumph, the victory of the soul over matter and man over nature, helped to establish, sustain, and perpetuate a vast heritage of spirituality. This was achieved, through the courageous pursuit of logical conclusions and intuitive, undetectable encounters outside the realm of reason. The experiences received from these learnings merged into a single principle that helped in human development. Upanishads are one of the oldest spiritual texts in Indian history, which helped man to live a life and build a society.

Frequently Asked Questions 

1. What do Dharma, Karma, Samsara, and Moksha Mean?
Ans:  Karma denotes a person’s response to an action. Dharma refers to a person’s obligations and responsibilities to society. Samsara, the cycle of both life and death, arises. Moksha is the ultimate goal of departing from the cycle of rebirth and death.

2. Who is the Upanishads’ Author?
Ans: The Upanishads’ author is still a mystery. The Upanishads are said to have been written by several authors. The scriptures were written with the help of famous sages like Aruni, Balaki, Sanatkumara, Yajnavalkya, and others.

3. Give the four Ashramas of the later Vedic Era.
Ans: The 4 ashrams of the Vedic period are-

• Brahmacharya: A phase in the Gurukul, the education process.
• Grihastha-A man was supposed to have a wife and children. Have a family life.
• Vanaprastha: A stage of life during which a person was supposed to put aside materialistic ambitions and relocate to the forests.
• Sanyasa: A man who abandons material interests to pursue exclusively spiritual objectives.

4. Give the names of the four Vedas. Which Veda is the Oldest?
Ans: The Rig Veda, Sama Veda, Yajur Veda, and Atharva Veda are the four Vedas of the Vedic era. The oldest of them all is the Rig Veda.