‘Write the electron configuration for phosphorus anion witn charge of – 3’
The Correct Answer and Explanation is:
Correct Answer:
The electron configuration of a phosphorus anion with a charge of -3 is:
1s² 2s² 2p⁶ 3s² 3p⁶
Detailed Explanation:
To write the electron configuration of a phosphorus anion (P³⁻), we first need to understand the atomic structure of a neutral phosphorus atom. Phosphorus has an atomic number of 15, which means it has 15 protons and, in a neutral state, 15 electrons. The electron configuration of a neutral phosphorus atom is:
1s² 2s² 2p⁶ 3s² 3p³
This shows that phosphorus has 3 electrons in its outermost p orbital (3p³), meaning it needs 3 more electrons to complete its octet and achieve the stable configuration of a noble gas.
When a phosphorus atom gains 3 additional electrons, it becomes a P³⁻ ion. The addition of these 3 electrons fills the 3p orbital, giving the phosphorus ion a total of 18 electrons. With these extra electrons, the electron configuration becomes:
1s² 2s² 2p⁶ 3s² 3p⁶
This is the same configuration as the noble gas argon (Ar), which is known for its chemical stability. Thus, the P³⁻ ion has a noble gas configuration, which is energetically favorable.
This electron configuration helps explain why phosphorus commonly forms a -3 charge in ionic compounds. Atoms tend to gain, lose, or share electrons to achieve a stable electron arrangement, often resembling the configuration of the nearest noble gas. In the case of phosphorus, gaining three electrons allows it to attain the same electron configuration as argon, making the P³⁻ ion stable in ionic bonds with positively charged ions, such as sodium (Na⁺) or calcium (Ca²⁺).
In summary, the P³⁻ ion has 18 electrons, and its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶, which reflects a stable, full outer electron shell.
