Question

What are the oxidation numbers of the elements in the nitrite ion

Answer 1

Answer : The oxidation number of nitrogen and oxygen in nitrite ion is, (+3) and (-2) respectively.

Explanation :

Oxidation number : It represent the number of electrons lost or gained by the atoms of an element in a compound.

Oxidation numbers are generally written with the sign (+) and (-) first and then the magnitude.

When the atoms are present in their elemental state then the oxidation number will be zero.

Rules for Oxidation Numbers :

The oxidation number of a free element is always zero.

The oxidation number of a monatomic ion equals the charge of the ion.

The oxidation number of  Hydrogen (H)  is +1, but it is -1 in when combined with less electronegative elements.

The oxidation number of  oxygen (O)  in compounds is usually -2, but it is -1 in peroxides.

The oxidation number of a Group 1 element in a compound is +1.

The oxidation number of a Group 2 element in a compound is +2.

The oxidation number of a Group 17 element in a binary compound is -1.

The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.

The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

The given molecule is, $NO_2^-$

Let the oxidation state of 'N' be, 'x'

$x+2(-2)=-1\\\\x-4=-1\\\\x=-1+4\\\\x=+3$

Therefore, the oxidation number of nitrogen and oxygen in nitrite ion is, (+3) and (-2) respectively.