Which of the following is the correct electron configuration for the potassium ion, K^+?

• A. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
• B. 1s^2 2s^2 2p^6 3s^2 3p^5
• C. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1
• D. 1s^2 2s^2 2p^6 3s^2 3p^6

Answer: (D)

Verified step by step guidance

1. Recall that the potassium atom (K) has an atomic number of 19, meaning it has 19 electrons in its neutral state.
2. Write the electron configuration for neutral potassium: \$1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$.
3. Understand that the potassium ion, \(K^+\), is formed by losing one electron from the neutral atom, so it will have 18 electrons.
4. Remove one electron from the outermost shell (which is the 4s orbital) because electrons are lost first from the highest energy level when forming cations.
5. The resulting electron configuration for \(K^+\) is \$1s^2 2s^2 2p^6 3s^2 3p^6$, which corresponds to the electron configuration of argon, a noble gas.