Write the symbol and valency of peroxide.
The peroxide ion, O22-, has a single oxygen-oxygen covalent link and the oxygen atoms have an oxidation state of -1.
Hence, the symbol of peroxide is O22- and its valency is -2.
Write the symbol and valency of nitride.
Write the symbol and valency of phosphite.
Write the symbol and valency of strontium.
Write the symbol and valency of bismuth.