Question

The total number of valence electrons in $4.2gm$ of $N_3^{-}$ ion are :

• A. $2.2N_A$
• B. $4.2N_A$
• C. $1.6N_A$
• D. $3.2N_A$

Answer 1

The correct option is C $1.6N_A$

As each molecule of $N_3^{-}$ has $16$ valence electrons.

Therefore, one mole will have $16$ mole of electrons.

Number of valence electrons = No. of moles $\times N_A\times$ valence electrons.

Here, $N_A$ is the Avagadro number.

$=\frac{4.2}{42}\times N_A\times 16$

$=1.6N_A$

Hence, option C is correct.