Question

Electrons are speed throughout the atom on different levels and subshells. The electron configuration for calcium is:
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$
According to this configuration, how many electrons are found on the valence level?

• A. $2$
• B. $6$
• C. $8$
• D. $20$

Answer 1

The correct option is A $2$

The valence shell is outermost shell. Thus valence shell of Calcium is fourth shell, and it has $2$ electrons in its valence shell. Thus there are $2$ valence electrons in Calcium and thus answer is option A.