Which of the following ions has the same electronic configuration as argon?

Question

Quizplus · Accepted Answer

Argon has an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶. K²⁺ would have lost two electrons from K, which has an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹, resulting in 1s² 2s² 2p⁶ 3s² 3p⁵, which is not the same as argon. Ca⁺ would have lost one electron from Ca, which has an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s², resulting in 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹, which is also not the same as argon.

Which of the Following Ions Has the Same Electronic Configuration