Question

How many valence electrons does the polyatomic ion nitrite, NO−2, have?

a) 16
b) 17
c) 18
d) 19

Answer 1

The nitrite ion, NO−2, has a total of 19 valence electrons, which includes the extra electrons from its negative charge.

Step-by-step explanation:

To determine how many valence electrons the polyatomic ion nitrite, NO−2, has, we can follow these steps:

• Count the valence electrons of the nitrogen atom: N (5 valence electrons).
• Count the valence electrons of the oxygen atoms: O (6 valence electrons each) × 2 = 12 valence electrons.
• Add the electrons due to the negative charge: 2 extra electrons for the −2 charge.
• Sum the valence electrons: 5 (from N) + 12 (from both O's) + 2 (additional due to charge) = 19 valence electrons.

The nitrite ion has a total of 19 valence electrons. When depicting this as a Lewis structure, it is displayed in a set of brackets with the charge of the ion as a superscript outside of the brackets.