7) 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

Option (d) chlorine has a greater ionization energy than sodium

Explanation:

Ionization energy is the energy required to remove an electron from a gaseous atom or ion. Sodium has just 1 electron in it's outmost shell and chlorine has 7.

Sodium needs 7 electrons to complete it's octet configuration and chlorine needs just 1.

Sodium can not attract 7 electrons to complete it's octet configuration instead it will easily lose the 1 electron in it's outmost shell to form cation. On the other hand, it will be difficult for chlorine to lose any of it's outmost electrons. This makes chlorine to have higher ionization energy than sodium.