Question

I. Ongoing from c to nin the second period, the values of electron affinity decreases instead of increasing.

Answer 1

Electron affinity decreases or increases across a period depending on electronic configuration. This occurs because of the same subshell rule that governs ionization energies. Example: Since a half-filled "p" subshell is more stable, carbon has a greater affinity for an electron than nitrogen.

Answer 2

The less valence electrons an atom has, the least likely it will gain electrons. Electron affinity decreases down the groups and from right to left across the periods on the periodic table because the electrons are placed in a higher energy level far from the nucleus, thus a decrease from its pull.