Question

6. What is the oxidation number of Ca(NO2)2?

Answer 1

Each of the different atoms in this compound have different oxidation numbers.
Oxygen is usually -2. Assign it first. Then, the sum of the oxidation numbers in the nitrite ion is the same as the charge on the ion. There are two oxygen atoms in the ion (2 x -2 = -4) and the ion caries a -1 charge, so the one nitrogen atom has to have an oxidation number of +3.
Two nitrite ions have a net charge of -2, so calcium has to have an oxidation number of +2. This works out nicely because the sum of the oxidation numbers in a neutral compound have to add up to zero.

Answer 2

thank you!!!

Answer 3

You're welcome.