Electrochemistry Practice Test

Oxidation states are assigned so that the sum of all oxidation numbers in a neutral compound is zero. Each chloride carries a -1 charge, so two chlorides contribute -2 total. To balance that and make the overall charge zero, tin must be +2. Tin can have multiple oxidation states, but in SnCl2 the two Cl− ligands fix the balance, giving tin a +2 oxidation state. If tin were +4, the total would be +2, not neutral; if tin were 0 or -2, the sum wouldn’t be zero either. So tin is +2.