Question

Find the total number of moles of electrons in $6.023\times {10}^{23}N{O}_3^{-}$ ions.

• A. 32
• B. 31
• C. 28
• D. 30

Answer 1

Answer: (A)

Nitrogen has 7 electrons, and Oxygen has 2 electrons, but there are 3 oxygen atoms so multiply 2 by 3. A negative charge on an ion indicates one extra electron. So, add all these numbers-

Total number of electrons in one $N{O}_3^{-}$ ion $=7+(8\times 3)+1=32$

So, the number of electrons in $6.023\times {10}^{23}N{O}_3^{-}$ ions are
$=6.023\times {10}^{23}\times 32$
$=$ 32 moles