Question

Nitrogen atom has an atomic number of 7 and oxygen has an atomic number of 8. The total number of electrons in a nitrate ion is

• A. 30
• B. 35
• C. 32
• D. None

Answer 1

Answer: (C)

32

Answer 2

Number of electrons in an element = Its atomic number

So number of electrons in N=7 and number of electrons in O=8.

Formula of nitrate ion is $NO_{3}^{-}$

So, in it number of electrons

$= 1 \times$ number of electrons of nitrogen $+ 3 \times$ number of electrons of oxygen +1 (due to negative charge)

$= 1 \times 7 + 3 \times 8 + 1 = 32$