Question #ed336

1 Answer
Nov 3, 2015

NN = +5; OO = -2; and the whole ion NO_3^-NO3 is -1.

Explanation:

Here are a few rules to remember when solving for oxidation state.

(1) The total charge of a stable compound is always equal to zero (meaning no charge).

For example, the H_2OH2O molecule exists as a neutrally charged substance.

(2) If the substance is an ion (either there is a positive or negative charge) the total oxidation state of the ion is the charge (i.e. oxidation state of NO_3^"-1"NO-13 ion is -1).

(3) All elements from Group 1A has an oxidation state of +1 (e.g. Na^"+1"Na+1, Li^"+1"Li+1). All Group 2A and 3A elements have an oxidation state of +2 and +3, respectively. (e.g. Ca^"2+"Ca2+, Mg^"2+"Mg2+, Al^"3+"Al3+)

(4) Oxygen always have a charge -2 except for peroxide ion (O_2^"2-"O2-2) which has a charge of -1.

(5) Hydrogen always have a charge of +1 if it is bonded with a non-metal (as in the case of HClHCl) and always have a -1 charge if it is bonded with a metal (as in AlH_3AlH3).

Now let's solve your problem.

Based on rule 2, the oxidation state of the NO_3^-NO3 ion is -1.

NO_3^-NO3 = -1

based on rule 4, the oxidation state of OO atom is -2.

xx + [(3) (-2)] = -1 where xx is the oxidation state of NN.

Notice that since OO atom has subscript, I needed to multiply the oxidation state by 3. Also, there are no rules for the oxidation state of NN so we need to solve it long hand.

xx + (-6) = -1
xx = -1 + (+6)
xx = +5

Therefore your oxidation states are NN = +5; OO = -2 and the whole ion NO_3^-NO3 is -1.