Question

give the full ground state electron configuration for potassium.

Explanation:

Step1: Recall potassium's atomic number

Potassium (K) has an atomic number of 19, which means it has 19 electrons in its ground - state.

Step2: Fill orbitals according to the Aufbau principle

Electrons fill orbitals in the order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s, 3d, etc. The s - orbitals can hold a maximum of 2 electrons, the p - orbitals can hold 6 electrons, and the d - orbitals can hold 10 electrons.
1s is filled first with 2 electrons: $1s^{2}$.
Then 2s is filled with 2 electrons: $2s^{2}$.
The 2p orbital is filled with 6 electrons: $2p^{6}$.
The 3s orbital is filled with 2 electrons: $3s^{2}$.
The 3p orbital is filled with 6 electrons: $3p^{6}$.
After filling 3p, the next electron goes into the 4s orbital (4s has lower energy than 3d for filling electrons initially). So the last electron goes into 4s, making it $4s^{1}$.

Answer:

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$