Question

Fe(NO3)2 not sure how to get the oxidation numbers of all elements

Answer 1

The oxidation number of iron (Fe) in the compound Fe(NO3)2 is +2. This is determined by knowing that the nitrate ion has a nitrogen atom with a +5 oxidation state, and since each nitrate ion has a -1 charge and there are two of them, the iron must balance the charge with a +2 oxidation number.

Step-by-step explanation:

The student asked how to determine the oxidation numbers of all elements in Fe(NO3)2. In this compound, iron (Fe) can have more than one oxidation state. However, we know that the nitrate ion (NO3¯) has a nitrogen atom with a +5 oxidation state because oxygen typically has an oxidation number of -2. Since the nitrate ion is a polyatomic ion with a charge of -1 and there are three oxygen atoms, the algebraic expression for the nitrogen oxidation number is x + 3(-2) = -1, solving for x gives us +5, which is nitrogen's oxidation number.

For Fe(NO3)2, we need to find the oxidation number of Fe. Since there are two nitrate ions (each with a net charge of -1) attached to the Fe, the combined charge of the nitrates is -2. To balance this, the Fe must have a +2 oxidation number so that the overall charge of the compound is neutral. The algebra for this is Fe2+ + 2(NO3¯) = 0, indicating that the iron oxidation number is +2.

Answer 2

You must remember that oxidation number of hydrogen in acids is always +1, oxidation number of oxygen in oxides & acids is always -2... metals has always oxidation number on plus!

group NO3 comes from HNO3...and oxidation number of whole acid group is always on minus and equal to the amount of hydrogen atoms in this acid... so oxidation number of NO3 = -1

we have 2 NO3 groups so 2*(-1) = -2 and that is the reason why oxidation number of Fe in this formula must be +2... because sum of all elements always gives 0!

Now we could count of oxidation number for nitrogen... we write HNO3 and start counting from right to left:
3*(-2) from oxygens + 1 from hydrogen = -5
so nitrogen must have +5 oxidation number... because sum all in formula must be 0.