Which has a higher ionization energy: chlorine (Cl) or magnesium (Mg)? Why? Select thebest answer.

Question

(1 point)
Cl; it takes much more energy to pull an electron away from a valence shell that is nearly full.
Mg; magnesium has more valence electrons than chlorine.
Mg; it takes more energy to pull two electrons away from magnesium(Mg) than it does to take
them from chlorine(Cl).
Cl; it takes less energy to add an electron to a valence shell that is nearly full.

Answer 1

The correct answer is:

Cl; it takes much more energy to pull an electron away from a valence shell that is nearly full.

This is because chlorine has seven valence electrons and is one electron short of a full octet, while magnesium has two valence electrons. When comparing ionization energies, elements with nearly full valence shells (like chlorine) typically have higher ionization energies than those with fewer electrons, due to the increased effective nuclear charge experienced by the electrons in the outer shell.