The electronic configuration of the element with highest electron affinity is;

Electron affinity (EA) is the amount of energy released when a neutral atom gains an extra electron to form a negative ion:

$EA\; =\; E(\backslash text\{atom\})\; -\; E(\backslash text\{atom\}^\{-\})$

When we compare EA values across the periodic table, the trend is:

• EA increases moving from left to right across a period, because the effective nuclear charge becomes larger and the added electron is attracted more strongly.

• EA generally decreases moving down a group, as the added electron is farther from the nucleus and experiences more shielding.

Among the first‑row elements, the halogens have the highest EA. Fluorine would seem a candidate, but its small atomic radius causes strong electron–electron repulsion in the added electron, making its EA slightly lower than that of chlorine.

Therefore, the element with the highest electron affinity is chlorine.

Chlorine’s ground‑state electron configuration is:

$[Ne] 3s2 3p5$

Removing the noble‑gas core notation, the configuration is written as:

3s² 3p⁵

Thus, the correct answer is the configuration 3s² 3p⁵, which corresponds to chlorine, the element with the highest electron affinity.