Sodium is much more apt to exist as a cation than chlorine because:

(a) chlorine is a gas and sodium is a solid
(b) chlorine has a greater electron affinity than sodium
(c) chlorine is bigger than sodium
(d) chlorine has a greater ionization energy than sodium
(e) chlorine is more metallic than sodium group of answer choices

Sodium is much more apt to exist as a cation than chlorine because chlorine has a greater electron affinity than sodium.

WHAT IS ELECTRON AFFINITY:

Electron affinity is a term used to describe the ability of a neutral atom to gain or attract electrons to become negatively charged. Atoms with high electron affinity tend to become negatively charged easily than those with low electron affinity. Chlorine atom (Cl) is known to have a high electron affinity, meaning that it is more difficult to become a cation (positively charged) than an atom like sodium with low electron affinity. Therefore, sodium is much more apt to exist as a cation than chlorine because chlorine has a greater electron affinity than sodium.

Learn more at: link

Ithink is d. physical property