Question

What is the electronic configuration of an element with atomic number $8$ ?

Answer 1

We have to remember that the atomic number of the atom is equal to the number of protons or the number of electrons. In every atom the number of protons and the number of electrons are equal. The electrons in the atom are filled by the lower energy level to the higher energy level.

Complete step by step answer:
We also remember that the atomic number $8$ and the total number of electrons is $8$. In this eight electrons, first two electrons are going to filled in the first energy level $1{s^2}$, remaining six electron are going to filled in the second energy level $2{s^2}2p_x^22p_y^12p_z^1$.
According to Pauli principle, Aufbau principle and Hund’s rule, the electronic configuration of the element with atomic number $8$ is $1{s^2}2{s^2}2p_x^22p_y^12p_z^1$.

Additional Information:
The following key points are to be remembered:
- In modern periodic table elements are arranged in the table depending on the atomic number. In this way only periods and rows are arranged in the modern periodic table.
The electron filling in the atomic orbital is followed by the three important principles: These are Pauli exclusion principle, Aufbau principle and Hund’s rule.
- In Aufbau principle, the electrons are filled in the orbital in the order of increasing the energy level of the orbital. First lower energy orbital filled followed by higher energy orbital are filled.
- In Pauli principle, no two electrons in the same orbital have the same quantum number.
- In Hund’s rule, the orbital must have more multiplicity than the pairing effect.

Note: We must know that the number of electrons in the atom is equal to the atomic number of the atom. The electron fills in the atomic orbital of the atom. Electrons are filled each electron in one orbital in the same energy level then it goes to a pair of electrons in the orbital.