Question

Which has a higher ionization energy: chlorine (Cl) or magnesium (Mg)? Why? Select the best answer.(1 point)
Responses

Cl; it takes less energy to add an electron to a valence shell that is nearly full.
Cl; it takes less energy to add an electron to a valence shell that is nearly full.

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

Answer 1

The best answer is:

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

Chlorine has a higher ionization energy than magnesium because it is closer to having a full valence shell (with 7 valence electrons) and thus requires more energy to remove one of its electrons. In contrast, magnesium has only 2 valence electrons and is more willing to lose them to achieve a stable electron configuration, which results in a lower ionization energy.