CLEP Chemistry

Answer: E. Sodium exists as Na⁺¹ because it’s then reached noble configuration. Thus, it’s hardest to remove a second ion from it (elements like noble configuration). While chlorine may have the highest first ionization energy (greatest electron affinity), it has more electrons to lose so second ionization energy is lower. Aluminum, phosphorus, and magnesium all have extra electrons to give away, too, before reaching noble configuration.
Sigma vs. Pi Bonds