13) Which element would be most likely to gain electrons in a chemical bond?

"Chlorine" is the element which is likely to gain electrons in a chemical bond.

Explanation:

In chlorine there are seven electrons in the valence shell, it requires one more electron so that it will become full valence and the electron will achieve the stability. For chlorine it will be easier to gain one electron and become stable than to loss all the seven electrons present in it to become stable. Also the non metals gain electrons and becomes negatively charged ions later known as the anions.