what is the oxidation number of P in H_2_PO_2_?

Answer 1

are you sure you wrote your chemical equation right? if it's h2po2 and it's a compund without any charge it could not exist. this compund is impossible. this is because oxygen always has a charge of 2-. so if oxygen has the negative charge, the rest must be positive. and the only possible oxidation states for phosphorus are 5+ and 3+. but if we use your "wrong" chemical equation, the oxidation state for P would be 2+ because the oxygen generates a total charge of 4- and the hydrogen generate 2+ so the phosphorus must generate the remaining 2+. are you sure your chemical equation isn't for phosphoric acid (h3po4) or phosphorous acid (h3po3)? if it is either one of those, the oxidation state is five and three respectively. your chemical equation contains hydrogen and po2. po2 is not a possible polyatomic ion and if it's an acid, then the two poossiblities i listed r probably what it is.

Answer 2

Most certainly you mean H3PO2, since H2PO2 does not exist.
H3PO2 has the following structure : 2 H atoms are connected to P directly. One o atom forms a "double" bond with P. The other H and O form a HO group. So oxidation number would be +1

Answer 3

+2

We know because H has one more electron than the closest noble gas, He. H, therefore, has to have an oxidation state of +1, so 2 H's would have a charge of +2.

The oxidation state of O is -2 because it has two less electrons than the closest noble gas, Ne. We have 2 O's, so they have a charge of -4.

Without P, the charge on the molecule is -4 + 2 = -2. P therefore has to carry a +2 charge to make the charge on the molecule equal zero.

Answer 4

The phosphorus has an oxidation number of +2 as the oxygens each "steal" 2 electrons but the Hydrogens each "donate" one electron from the phosphorus.