Final answer:
The complete electron configuration of a potassium ion (K+) is 1s2 2s2 2p6 3s2 3p6, which reflects the noble gas configuration of argon (Ar) after losing one electron.
Step-by-step explanation:
The electron configuration for a potassium ion (K+) reflects the loss of one electron from the neutral atom's configuration. Potassium, with an atomic number of 19, has the electron configuration of [Ar]4s1 for the neutral atom. However, when it loses an electron to form a K+ ion, it achieves the noble gas configuration of argon, resulting in the electron configuration [Ar], which is equivalent to 1s2 2s2 2p6 3s2 3p6. Therefore, the complete electron configuration of a potassium ion is 1s2 2s2 2p6 3s2 3p6, which can also be referred to as the noble gas configuration of argon (Ar).