Question

Given the following electron configuration of a neutral atom:
$\left[Ar\right]4s^{1}3d^5$
Identify the element and state the number of unpaired electrons in the ground state.

• A. Chromium $\left(Cr\right),4$ unpaired electrons in the ground state.
• B. Chromium $\left(Cr\right),5$ unpaired electrons in the ground state.
• C. Chromium $\left(Cr\right),6$ unpaired electrons in the ground state.
• D. Manganese $\left(Mn\right),5$ unpaired electrons in the ground state.

Answer 1

The correct option is C Chromium $\left(Cr\right),6$ unpaired electrons in the ground state.

The given element has $18\left(Ar\right)+1+5=24$ electrons i.e., the element is Cr. Its outermost shell diagram is (image). Thus the Cr atom has $6$ unpaired electrons. Hence answer is option C.