Question

If $N_A$ is the Avogadros number then number of valence electrons in 4.2 g of nitride ions $N^{3-}$ is _________.

• A. 2.4 $N_A$
• B. 4.2 $N_A$
• C. 1.6 $N_A$
• D. 3.2 $N_A$

Answer 1

Answer: (A)

2.4 $N_A$

No of moles $=\frac{4.2}{14}=0.3$ mol

$0.3mol=0.3\times N_A$ ions

$=8\times 0.3\times N_A$ electrons

$=2.4N_A$ electrons

Because each ion contains $5+3=8e^{-}$