Question

draw the electron configuration for a neutral atom of cobalt.

Explanation:

Step1: Determine the atomic number of cobalt

Cobalt (Co) has an atomic number \( Z = 27 \). A neutral atom has the number of electrons equal to the atomic number, so \( n = 27 \) electrons.

Step2: Fill the orbitals according to the Aufbau principle, Pauli exclusion principle, and Hund's rule

• Fill the \( 1s \) orbital first. The \( 1s \) orbital can hold \( 2 \) electrons: \( 1s^{2} \).
• Then the \( 2s \) orbital (holds \( 2 \) electrons): \( 2s^{2} \).
• Next, the \( 2p \) orbitals (3 sub - orbitals, each can hold 2 electrons, total \( 6 \) electrons): \( 2p^{6} \).
• Then the \( 3s \) orbital (holds \( 2 \) electrons): \( 3s^{2} \).
• Next, the \( 3p \) orbitals (holds \( 6 \) electrons): \( 3p^{6} \).
• Then the \( 4s \) orbital (holds \( 2 \) electrons): \( 4s^{2} \).
• After filling \( 4s \), fill the \( 3d \) orbitals. There are \( 27-(2 + 2+6 + 2+6 + 2)=7 \) electrons left for the \( 3d \) orbitals. According to Hund's rule, we first half - fill the \( 5 \) \( 3d \) sub - orbitals and then pair up. So the \( 3d \) configuration is \( 3d^{7} \).

The electron configuration of a neutral cobalt atom is \( 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{7} \).

Answer:

The electron configuration of a neutral cobalt atom is \( 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{7} \).