Question

Which is the correct Lewis dot structure of NH2-?

Answer 1

Answer: The correct answer is Option D.

Explanation:

Lewis dot structures are the structures which represent the valance electrons of an element forming a compound. The electrons are represented as the dots.

In a compound, the bonded electrons are represented as a bond and lone pair of electrons are represented as dots.

In $NH_2^-$ compound,

Electronic configuration of Nitrogen: $1s^22s^2p^3$

Valence electrons in nitrogen = 5

Electronic configuration of hydrogen: $1s^1$

Valence electrons in hydrogen = 1

In the given compound, bond pairs are 2 which means number of electrons bonded are 4.

Unbonded electrons left on nitrogen will be 3 and this compound has an extra electron because of the negative charge present on the compound. Hence, total unbonded electrons present on this compound will be 4.

Therefore, the lewis dot structure will be Option D.

Answer 2

D. The total number of valence electrons is 8 and D represents that. D also correctly uses the octet rule for N and duet rule for H.