Electron Configuration Practice Test 2025 – Complete Exam Prep

The correct answer, which pertains to which element fills the p orbital to its maximum of 6 electrons, is Argon.

In the context of electron configuration, the p orbitals can hold a maximum of 6 electrons because they consist of three distinct p subshells (denoted as p_x, p_y, and p_z), each of which can hold 2 electrons. Thus, when we talk about filling the p orbital, we are referring to the total occupancy of these three subshells.

Argon, which has an atomic number of 18, has the electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶. The 3p subshell, which is part of Argon’s configuration, is fully occupied with 6 electrons. This distinguishes Argon as a noble gas with a complete outer electron shell, leading to its stability and low reactivity.

In contrast, Chlorine, Carbon, and Neon do not fill the p orbital to its maximum capacity. Chlorine has an additional electron in its 3p subshell (with the configuration ending in 3p⁵), which means it is one electron short of filling that subshell.