Question

How many d-electrons in Cu+ (At. No=29) can have the spin quantum number $\left( {\dfrac{{ - 1}}{2}} \right)$?
A. 3
B. 7
C. 5
D. 9

Answer 1

Hint- To solve this question, we use the basic theory related to the chapter atomic structure. As we know the d electron is used in atomic configuration to describe the electron configuration of the valence electrons of an element. The d electron count is a very easy way to understand the geometry and reactivity of transition metal complexes in electron configuration.

Complete step-by-step answer:
Spin slate refers to the potential spin configurations of the central metal's d electrons when describing transition metal coordination complexes.
Any atom can consist mainly of three particles like electron, neutron and proton. The proton present in the nucleus (center) of the atom and proton is a positively charged particle. Electrons are the outermost regions of the atom which are negatively charged. And neutrons are neutrally charged particles.
The electron 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.
Proton is discovered by Ernest Rutherford (1917–1920), Electron is discovered by J.J. Thomson in 1897 and Neutron was discovered by Chadwick In February 1932.
The sum total of all the electrons in the highest energy level is called Valence electrons. Some transition metals have an electron configuration that is $ns^2(n-1)d$
So, we know that the electronic configuration of $C{u^ + }$ is [Ar] $3{d^{10}}$. In this electronic configuration $C{u^ + }$ has ten d elements. Out of these, one half, of this will have 5 which will have the spin quantum number.
$\left( {\dfrac{{ - 1}}{2}} \right)$ and the rest half will have the spin quantum number $\left( {\dfrac{{ - 1}}{2}} \right)$
Therefore, we conclude that the option(C) is the correct answer.

Note- In atomic structure, The Spin Quantum Number describes the overall angular momentum of an electron. An electron spins around an axis and has both angular momentum as well as orbital angular momentum. Because angular momentum is a vector quantity, the Spin Quantum Number (s) may have both magnitude and direction (+ or -).