Question

which element has the electron configuration (1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{5})?

Explanation:

Step1: Calculate the total number of electrons

The electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{5}\).
Sum the exponents: \(2 + 2+6 + 2+6 + 2+5=25\).

Step2: Determine the element based on atomic number

The number of electrons in a neutral atom is equal to its atomic number.
An element with atomic number \(25\) is manganese (\(Mn\)).

Answer:

D. Mn