5) Chlorine has 7 valence electrons. Neon has 8 valence electrons. Which on is more likely to undergo a chemical reaction, and why?

well, chlorine will undergo in a chemical reaction

Explanation:

neon has completed valence shells, so it neither need electron and or it also don't need to donate the electrons. hence it will not participate in any chemical reaction and it is stable in nature.

whereas chlorine need one more electron to complete it's valence shell and in order to be stable , so it will try to gain one electron , hence

it will take place in a chemical reaction