Hydrides react with water, so there are no hydrides found in nature. The formula XH or XH 2 or XH 3 or even XH 4 where X is a metal is the general chemical formula for hydride. Diatomic gases such as O 2 and H 2 are also in this category. All compounds have a net oxidation state of zero. The oxidation state of all of the atoms add up to zero.
Any ion has the oxidation state that is the charge of that ion.
Oxygen in compound has an oxidation state of minus two, except for oxygen as peroxide, which is minus one. 5. Hydrogen in compound has an oxidation state of plus one, except for hydrogen as hydride, which is minus one. In radicals or small covalent molecules, the element with the greatest electronegativity has its natural ion charge as its oxidation state. Now would be a good time to try the oxidation state problems beginning the practice page at the end of this chapter. Problems 1-30 are good examples for practice of assigning oxidation states.