🤓 Based on our data, we think this question is relevant for Professor Donadio's class at UCD.
We’re being asked to determine the oxidation state of phosphorus in PO43– (phosphate ion).
The rules for oxidation states are as follows:
A. General Rules:
1. For an atom in its elemental form (Zn, Cl2, C(graphite), etc.) O.S. = 0
2. For an ion (Li+, Al3+, etc.) O.S. = charge
B. Specific Rules:
1. Group 1A O.S. = +1
2. Group 2A O.S. = +2
3. Hydrogen O.S. = +1, with nonmetals
O.S. = –1 with metals and boron
4. Fluorine O.S. = –1
5. Oxygen O.S. = –1 in peroxides (X2O2, X = Group 1A)
O.S. = –1/2 in superoxides (XO2, X = Group 1A)
O.S. = –2 in other compounds
6. Group 7A O.S. = –1 (except when bonded to O)
Since PO43– is neither a peroxide or superoxide, the oxidation state of each oxygen atom is –2.
What is the oxidation number of phosphorus in PO43−?