And so it precedes this table. But let's look at the general guidelines. So the group number one, the alkali metals are assigned an oxidation state of plus one. Group number two, the alkali earth metals are assigned oxidation state of plus two. So group number 15, including nitrogen, phosphorus, and so on, are assigned an oxidation state of negative three. Group number 16, including oxygen, sulfur, and so on, are a sign oxidation state of negative two.