Question

Identify the group and period of the element with atomic number 12.

• A. IA, third
• B. IIIA, third
• C. IIA, third
• D. IIA, second

Answer 1

Answer: (C)

IIA, third

The electronic configuration of the element with atomic number 12 is $1s^{2}2s^{2}2p^{6}3s^2$.

The number of valence electrons $=2$, which means it belongs to group II A.

The valence shell is 3, which means it belongs to the third period.