Why do you think the Cl -ion is larger than a neutral Cl atom?

Cl- (having a larger number of electrons with the same number of protons means that there will be less of a pull on the valence electrons from the nucleus. This means it will become larger).

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72