Which of the following correctly represent the electronic distribution in the Mg atom?

1. 3, 8, 1
2. 2, 8, 2
3. 1, 8, 3
4. 8, 2, 2

### Answer

Atomic number and the number of electrons in magnesium atom is 12.

So, electronic configuration is 2, 8, 2 (because 12 = 2 + 8 + 2).

The correct option is B.