Assertion (A) claims that electron affinity always increases from top to bottom in a group in the periodic table. This is false. Electron affinity generally decreases down a group due to the increasing atomic size and electron shielding, which reduce the attraction for an incoming electron. Reason (R) states that in a group, the atomic radii generally increases from top to bottom. This is true. As you move down a group, new electron shells are added, leading to a larger atomic size.
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.
Asked in UPPCS Prelims 2003 · Topic: Atomic Structure (Electronic Configurations of Multi-electron Atoms and Ions)
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