Question

In which species does phosphorous have an oxidation number of zero? In which species does phosphorous have an oxidation number of zero? P4 (elemental phosphorous) HPO2 Li3PO3 H3PO4 PH3

Answer 1

`P_4`

Explanation:

Phosphorus in `P_4` has a oxidation number of zero.

This is because every element in its elemental state has zero oxidation state.

Answer 2

`P_4`

Explanation:

In `P_4` the electron density is shared equally between all of the atoms of Phosphorus leaving all them with zero oxidation state.

In `HPO_2` Phosphorus has a charge of +3

`H = 1 xx H = 1 xx + 1 = +1`
`O_2 = 2 xx O = 2 xx -2 = -4`

`+1 + P + -4 = 0` ( a compound always = 0)

`P +1 -4 = 0`

`P - 3 = 0` adding 3 to both sides gives

`P = +3`

In `Li_3PO_3` P has a charge of +3
`Li_3 = 3 xx Li = 3 xx + 1 = +3`
`O_3 = 3 xx O = 3 xx -2 = -6`

`+3 + P + (-6) = 0`

`P + 3 -6 = 0`

`P - 3 = 0` adding 3 to both sides gives

`P = +3`

In `H_3 P O_4` P has a charge of +5

`H_3 = 3 xx H = 3 xx +1 = +3`
`O_4 = 4 xx O = 4 xx -2 = -8`

`+ 3 + P + (-8) = 0`

`P + 3 -8 = 0`

`P -5 = 0` adding five to both sides gives

`P = +5`

in `PH_3` P = -3
`H_3 = 3 xx H = 3 xx +1 = +3` so

`P + 3 = 0` subtract 3 from both sides gives

`P = -3`

All the other compounds give species of phosphorus that have non-zero oxidation state.Only phosphorus in elemental phosphorus has zero oxidation state .