Give the Chemical formula for Sulphur dioxide
Symbol: S O
Valency: +4 -2
We can use the criss-cross method to find out the chemical formula of a metal and non-metal that combine to form an ionic bond. By this method, the absolute value of the oxidation number of the first ion is used as the subscript of the second, and vice versa. So, we get the formula as
The subscripts are then reduced by the greatest common factor by which we get the formula of the compound as SO2.