Find the element’s group on the periodic table
For main-group elements, use the group number to estimate common ion charge
Group 1 elements usually have a charge of +1
Group 2 elements usually have a charge of +2
Group 13 elements usually have a charge of +3
Group 15 elements usually have a charge of -3
Group 16 elements usually have a charge of -2
Group 17 elements usually have a charge of -1
Group 18 elements usually have a charge of 0
Transition metals can have multiple charges
Check the Roman numeral in the compound name for transition metal charge
Use the total charge of a compound to solve for an unknown element charge
For a neutral compound, all charges must add to 0
For a polyatomic ion, use the ion’s overall charge as the sum of its parts