1. Determine Phosphorus's Electron Configuration in PCl3
* Phosphorus (P) has 15 electrons. Its ground state electron configuration is: 1s² 2s² 2p⁶ 3s² 3p³
* In PCl3, phosphorus forms three single bonds with chlorine atoms. This means it shares three of its valence electrons.
* Phosphorus's electron configuration in PCl3 is effectively 1s² 2s² 2p⁶ 3s² 3p⁶ (since it's sharing the three electrons).
2. Identify the Noble Gas with the Same Configuration
* The noble gas with the electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ is Argon (Ar).
Therefore, Argon (Ar) has the same electron configuration as phosphorus in a PCl3 molecule.
