Question

What are the oxidation numbers of $Fe,N$ and $O$ in $Fe{(N{O_3})_3}$ ?

Answer 1

Oxidation number is also known as oxidation state which can be defined as the number of electrons that an atom, molecule or ion can lose or gain or share when it forms chemical bonds with another atom of any different element or same element. Oxidation number can be negative or positive or it can be zero.

Complete answer:
Oxidation number is also known as oxidation state which can be defined as the number of electrons that an atom, molecule or ion can lose or gain or share when it forms chemical bonds with another atom of any different element or same element.
We know that an electronegative element will have a negative oxidation state while an electropositive element will have a positive oxidation state.
If we consider the given salt: $Fe{(N{O_3})_3}$
When salt dissociates, we get
$Fe{(N{O_3})_3} \to F{e^{3 + }} + 3{(N{O_3})^ - }$
Therefore, we can see that, $Fe$ shows an oxidation state of $+ 3$ .
When we take anionic part of the salt: $NO_3^ -$
We know that oxygen is more electronegative than nitrogen, so it will have its general oxidation state which is $- 2$ .
Now, we will find out the oxidation state of nitrogen by substituting method as follows:
Let the oxidation state of nitrogen be $x$ .
$x + (( - 2) \times 3) = - 1$
$x = - 1 + 6$
$x = + 5$
Therefore, the oxidation states of $Fe,N$ and $O$ in $Fe{(N{O_3})_3}$ are $+ 3, + 5$ and $- 2$ respectively.

Note:
We should remember that the oxidation states of elements can be determined according to their nature such as electronegative and electropositive. Electronegative elements mostly possess negative oxidation states as they can gain electrons easily while electropositive elements mostly possess positive oxidation states as they can lose electrons easily.