Enter the full electron configuration for P3-. (2) What is the atomic symbol for the noble gas that also has this electron configuration?
The Correct Answer and Explanation is:
Full Electron Configuration for P3-:
The P3- ion is formed when a phosphorus atom gains three electrons, making it negatively charged. A neutral phosphorus atom has an atomic number of 15, so it has 15 electrons. The electron configuration for neutral phosphorus is:
1s² 2s² 2p⁶ 3s² 3p³
When phosphorus gains three electrons to form the P3- ion, it will have a total of 18 electrons. To reflect this addition, we update the electron configuration:
1s² 2s² 2p⁶ 3s² 3p⁶
This is the electron configuration for the P3- ion, which is the same as the electron configuration of argon (Ar), a noble gas.
Atomic Symbol for the Noble Gas:
The atomic symbol for the noble gas that has the same electron configuration as the P3- ion is argon (Ar). Argon has an atomic number of 18, and its electron configuration is:
1s² 2s² 2p⁶ 3s² 3p⁶
Since both P3- and Ar have the same electron configuration, they are considered isoelectronic, meaning they contain the same number of electrons and therefore exhibit similar chemical properties.
Explanation:
- The electron configuration is the arrangement of electrons in an atom or ion’s orbitals.
- Phosphorus (P) typically has the electron configuration 1s² 2s² 2p⁶ 3s² 3p³, with 15 electrons in total.
- When phosphorus gains 3 electrons, it becomes the P3- ion, which now has 18 electrons, and the configuration becomes 1s² 2s² 2p⁶ 3s² 3p⁶.
- This electron configuration is identical to that of argon, a noble gas. Noble gases have full outer electron shells, which makes them chemically stable.
- The term “isoelectronic” describes ions or atoms that have the same number of electrons, and thus similar electron configurations.
