Charge on Ions This table summarizes the charge of ions formed by representative elements.

GroupNumber of valence electrons
gain or lose electrons
charge of ionsexamples
IA
1
lose 1 electron
+1
H+, Li+, Na+, K+
IIA
2
lose 2 electrons
+2
Mg+2, Ca+2, Sr+2
IIIA
3
lose 3 electrons
+3
Al+3, Ga+3
IVA
4
Group IVA elements have a tendency to share electrons instead of gaining or losing valence electrons
VA
5
gain 3 electrons
-3
N-3, P-3
VIA
6
gain 2 electrons
-2
O-2, S-2
VIIA
7
gain 1 electron
-1
F-, Cl-
VIIIA
Complete octet makes the noble gases unreactive