Periodic Table, Periodic Properties and Variations of Properties — Chemistry STD 10 — Question

(d) Br
Explanation : In general, electron affinity increases across a period from left to right in the periodic table because the atoms become more prone or unstable to gain an electron in order achieve a stable electronic configuration, like that of the noble gases. Halogens like bromine (Br), has to high electron affinity because it requires one electron to complete its octet. Noble gases, like argon (Ar) have full filled outer shell, and metals, such as magnesium (Mg) and lithium (Li), show lower tendencies to lose electrons.