Question

How can you find the electron configuration of $Zn$?

Answer 1

Hint The answer to this question lies in the concept of chemistry which tells about writing the electron configuration based on knowing the atomic number and based on the Aufbau principle.

Complete step – by – step answer:
In the previous chapters of general chemistry, we have studied about the finding of the number of protons, neutrons and electrons and also about several rules assigned for the filling of electrons in an orbital like Pauli’s exclusion principle, Aufbau principle and so on.
We shall see what Aufbau principle is and based on this let us write the electronic configuration of the given atom.
- Zinc is having the atomic symbol $Zn$ which has the atomic number 30 and therefore belongs to the group of transition elements.
- Here, to write the electronic configuration, the rules assigned by Aufbau principle are to be noted.
- Aufbau principle states that in the ground state of an atom or the ion, electrons will fill the atomic orbitals of the lowest available energy levels before occupying the higher energy levels.
- The 1s subshell has to be filled first before the 2s subshell and so on. The electronic configuration for zinc with total of 30 electrons can be written as $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^2$
Here, the 4s subshell is filled first before filling the 3d shell according to the Aufbau principle.

Therefore, the correct answer is electron configuration of $Zn$ is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^2$

Note: Note that the electronic configuration of the bigger atoms can be written in the form of shorthand notation which is nothing but writing the valence electrons outside which is preceded by the noble gas configuration of the remaining electrons written in square brackets and for zinc it is $[Ar]3d^{10}4s^2$