"There are two ions per formula unit in this compound. The -1 anion has 8 more electrons than the cation."

I need to find the Chemical formula/name.
Any suggestions on how to start?
This can have more than one correct answer.

2 answers

I would think MX would represent the compound. That is two ions per formula unit. If X is -1, then M must be +1. That would suggest M would be a group I metal and X would be a group 17 ( or group VIIA sepending upon the system you are using) element. So just pick Na^+ would have 10 electrons (11 -1 = 10) and Cl^- would have 18 (17 + 1 = 18) and that is 8 more electrons for X then for M. I would think, without trying it, that Li and F would work, also.
NaCl