These are all different compounds containing the element zinc. Here is a breakdown of each compound:

Zn - This is the chemical formula for zinc, which is the pure elemental form of the metal.

ZnCl2 - This is zinc chloride, a chemical compound made of zinc and chlorine atoms.

Zn(NO3)2 - This is zinc nitrate, a chemical compound made of zinc, nitrogen, and oxygen atoms.

ZnSO4 - This is zinc sulfate, a chemical compound made of zinc, sulfur, and oxygen atoms.

Zn(OH)2 - This is zinc hydroxide, a chemical compound made of zinc, oxygen, and hydrogen atoms.

ZnO - This is zinc oxide, a chemical compound made of zinc and oxygen atoms.

K2ZnO2 - This is potassium zincate, a chemical compound made of potassium, zinc, and oxygen atoms.

Each of these compounds has different properties and uses in various industries.