Question

The electron affinity of an atom
a) directly proportional to its size
b) inversely proportional to its size
c) is independent of its size
d) none of these

Answer 1

Answer ⇒ Option (b). Inversely Proportional to its size. 

Electron affinity ∝ 1/Atomic Size of the atom. 

Explanation ⇒ 

Electron affinity of the atom is inversely proportional to the atomic size. This means that if the size of the atom decreases then the nuclear charge increases, as a result of which less energy is required to add the electrons, Hence, the electron affinity increases.  

Due to the above given reason only, Electron affinity increases as one move from left to rights in any periods and it decreases as one move from the top to the bottom in any group of the Periodic Table. 

Hence, Option (b). is correct. 


Hope it helps.

Answer 2

Answer ⇒ Option (b). Inversely Proportional to its size. 

Electron affinity ∝ 1/Atomic Size of the atom.