What is the ground state electron configuration of Chlorine (Cl)?

To determine the ground state electron configuration of Chlorine (Cl), it is essential to know the atomic number of chlorine, which is 17. This means that a neutral chlorine atom contains 17 electrons. The electrons fill the atomic orbitals following the Aufbau principle, filling lower energy levels before moving to higher ones.

The correct electron configuration for chlorine is 1s² 2s² 2p⁶ 3s² 3p⁵. In this configuration, the distribution of electrons is as follows:

• The 1s subshell can hold a maximum of 2 electrons, which it does (1s²).

• The 2s subshell also holds 2 electrons (2s²).

• The 2p subshell can accommodate a total of 6 electrons, and it is filled completely (2p⁶).

• Moving to the third energy level, the 3s subshell holds another 2 electrons (3s²).

• Finally, the 3p subshell, which can hold up to 6 electrons, contains 5 electrons (3p⁵), leaving it one short of being full.

Therefore, the combination of electrons in these orbitals sums up to 17: