Question

which element would most likely have an electron affinity measuring closest to zero?
na
al
rb
ar

Explanation:

Electron affinity is the energy change when an electron is added to a neutral atom in the gaseous state. Noble gases have a full - valence electron shell. Adding an electron to a noble gas would require forcing the electron into a new, higher - energy shell, which is highly unfavorable. Argon (Ar) is a noble gas. Sodium (Na), aluminum (Al), and rubidium (Rb) are metals and are more likely to lose electrons rather than gain them easily, but their electron affinities are not as close to zero as that of a noble gas due to their incomplete valence shells.

Answer:

Ar