Answer:
3A: c
7A: d
1A: b
6A: f
2A: e
5A: a
Explanation:
3A: needs to -3 electrons to be stable, so +3 charge
7A: needs to +1 electrons to be stable, so -1 charge
1A: needs to -1 electrons to be stable, so +1 charge
6A: needs to +2 electrons to be stable, so -2 charge
2A: needs to -2 electrons to be stable, so +2 charge
5A: needs to +3 electrons to be stable, so -3 charge
ALL 8A ELEMENTS ARE STABLE, THEY HAVE THEIR VALENCE SHELL FULLY FILLED
