Question

In the cyanide ion (cn-), the nitrogen has a formal charge of

Answer 1

Answer : The formal charge on nitrogen atom is Zero (0).

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is,
`CN^-`

As we know that carbon has '4' valence electrons and nitrogen has '5' valence electrons.

Therefore, the total number of valence electrons in
`CN^-` = 4 + 5 + 1 = 10

According to Lewis-dot structure, there are 6 number of bonding electrons and 4 number of non-bonding electrons.

Now we have to determine the formal charge for each atom.

Formula for formal charge :

`\text{Formal charge}=\text{Valence electrons}-\text{Non-bonding electrons}-\frac{\text{Bonding electrons}}{2}`

`\text{Formal charge on C}=4-2-(6)/(2)=-1`

`\text{Formal charge on N}=5-2-(6)/(2)=0`

Hence, the formal charge on nitrogen atom is Zero (0).

Answer 2

CN- looks like this using a Lewis structure

=- is a triple bond

:C=-N: Nitrogen has 5 valence electrons

You’ll take 5 and subtract the amount of unshared and 1/2shared

So it’ll be 5 - (2 + 1/2(6))= 0

So the Nitrogen has a neutral charge