Below is the Lewis structure of the hydrogen cyanide molecule.
H: C ::: N :

Count the number of bonding pairs and the number of lone pairs around the hydrogen atom in this molecule.

Answer :

The number of bonding pairs of electrons around the hydrogen atom = 2

The number of lone pairs of electrons around the hydrogen atom = 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,

As we know that carbon has '4' valence electrons, hydrogen has '1' valence electrons and nitrogen has '5' valence electrons.

Therefore, the total number of valence electrons in = 1 + 4 + 5 = 10

According to Lewis-dot structure we conclude that, there are 8 number of bonding electrons and 2 number of non-bonding electrons.

The number of bonding pairs of electrons around the hydrogen atom = 2

The number of lone pairs of electrons around the hydrogen atom = 0

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons