Final answer:
The electron configuration of a neutral chlorine atom is 1s² 2s² 2p⁶ 3s² 3p⁵, which allows it to gain an electron to form a chloride ion with a stable noble gas configuration.
Step-by-step explanation:
The electron configuration of a neutral chlorine atom reflects its distribution of electrons among the various orbitals. A chlorine atom has a total of 17 electrons. Following the Aufbau principle, the electrons are placed in orbitals starting with the lowest energy first:
2 electrons fill the 1s orbital: 1s²
2 electrons fill the 2s orbital: 2s²
6 electrons fill the 2p orbitals: 2p⁶
2 electrons fill the 3s orbital: 3s²
5 electrons fill the 3p orbitals: 3p⁵
This gives us the full electron configuration for a neutral chlorine atom: 1s² 2s² 2p⁶ 3s² 3p⁵. Additionally, the chlorine atom can gain an electron to achieve the noble gas electron configuration, forming a chloride ion with the configuration [Ne]3s² 3p⁶.