Question

How many d electrons are present in $Cu^{2+}$ ion?

Answer 1

Hint The number of electrons present in the last shell of an atom is known as valence electrons. In order to solve this question, we must remember that the d electrons is used in atomic configuration to describe the electron configuration of the valence electrons of an element.

Complete step by step answer:
- The atomic number of Copper is 29. So, the expected configuration of copper ion is
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{9}$
- It can also be represented as
$[Ar]4s^{2}3d^{9}$
- But as we know that the half-filled configuration gets extra stability. So, one of the electrons of $4s^{2}$ jumps to $3d^{9}$. So, the configuration will be
$[Ar]4s^{1}3d^{10}$
- Since $Cu^{2+}$ ion suggests that copper loses two electrons. So, one electron will be removed from 4s subshell and 3d subshell each.
- Therefore, the configuration would be
$[Ar]4s^{0}3d^{9}$
- Now we know that the d subshell of copper ions consists of 9 electrons.

Additional information:
Electronic configuration is the arrangement of electrons in the atomic or molecular orbitals of atoms or molecules. This arrangement of electrons, into different shells and subshells, is called electronic configuration.

Note: The electronic configuration of any element is determined by the charge of the nucleus, set by the number of protons in an element, or atomic number of elements. In this case, one electron jumps from 4s subshell to the 3d subshell in order to attain stability