Question

The number of unpaired electrons present in the first excited state of chlorine atom is:

• A. $1$
• B. $3$
• C. $5$
• D. $2$

Answer 1

Answer: (B)

$3$

The number of unpaired electrons present in the first excited state of the chlorine atom is 3. The electronic configuration of chlorine is $\left[Ne\right]3s^{2}3p_x^{2}3p_y^{2}3p_z^1$. Thus, it contains 1 unpaired electron. In the first excited state, 1 electron is transferred from 3p to 4s orbital. The electronic configuration becomes $\left[Ne\right]3s^{2}3p_x^{2}3p_y^{1}3p_z^{1}4s^1$ Thus, three unpaired electrons are present in the excited state.