* Atomic Number: 19

* Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

Explanation:

* 1s²: The first energy level (n=1) has one subshell (s) which can hold up to 2 electrons.

* 2s²: The second energy level (n=2) has two subshells (s and p). The s subshell holds 2 electrons.

* 2p⁶: The p subshell in the second energy level can hold up to 6 electrons.

* 3s²: The third energy level (n=3) has two subshells (s and p), with the s subshell holding 2 electrons.

* 3p⁶: The p subshell in the third energy level can hold up to 6 electrons.

* 4s¹: The fourth energy level (n=4) starts with the s subshell, which holds 1 electron for potassium.

Important Note: Potassium's electron configuration might seem a little unusual since it has a single electron in the 4s orbital instead of filling the 3d orbitals first. This is because the 4s orbital is slightly lower in energy than the 3d orbitals, making it more stable to have the electron in the 4s orbital.