Assertion (A): In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group. Reason (R): In a group, the atomic radial generally increases from top to bottom.
- ABoth A and R are individually true and R is the correct explanation of A
- BBoth A and R are individually true but R is NOT the correct explanation of A
- CA is true but R is false
- DA is false but R is trueCorrect
Explanation
The correct answer is D because the assertion is false while the reason is true.
In the periodic table, electron affinity generally decreases from top to bottom in a group, not increases. This is because as you move down a group, the atomic radius increases due to the addition of new electron shells. This increase in atomic radius means the nucleus is farther away from the outermost shell, making it harder for the atom to attract and bind an incoming electron. Therefore, while the reason correctly describes the trend of atomic radii, the assertion incorrectly describes the trend of electron affinity.
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