Question

What is the electronic configuration for a phosphorus anion with a charge of \[ - 2\] ?

Answer 1

Hint: When an atom accepts one or more electrons to gain stability the number of electrons becomes greater than the number of protons in an atom due to which it becomes negatively charged anion is called an anion. Anions are also known as nucleophiles and act as reaction intermediates in various organic reactions.

Complete answer:
Phosphorus: It is a chemical element represented by the symbol \[P\]. It exists in two major forms i.e., white phosphorus and red phosphorus. Due to its highly reactive nature, it is never found as a free element.
The electronic configuration of an element must be written according to Aufbau’s principle and Hund’s rule which are explained as follows:
Aufbau Principle- It states that the filling of electrons should be done according to increasing energy level of orbitals i.e., orbitals with lower energy will be filled first than the orbitals with higher energy.
Hund’s Rule- The pairing of electrons in a subshell will take place only when all the subshells in an orbital are singly filled.
The atomic number of phosphorus atom \[ = 15\]
Electronic configuration of phosphorus atom \[ = 1{s^2}2{s^2}2{p^6}3{s^2}3{p^3}\]
A charge of \[ - 2\] on a phosphorus atom represents the addition of two electrons in the valence shell of the atom. Therefore, the electronic configuration of phosphorus anion with a charge of \[ - 2\] is as follows:
\[{P^{2 - }} = 1{s^2}2{s^2}2{p^6}3{s^2}3{p^5}\]

Note:
Whenever an atom loses or gains an electron, this moving of electrons always takes place in the valence shell of an atom i.e., the shell in which the last electron of a neutral atom is filled. The charge present on the atom is also considered as its oxidation state.