Question

Identify which of the following configurations holds good for zinc.

• A. x, (x+y), 3y, x
• B. x, (x+y), 3y, (x-1)
• C. x, y, (3y-1), x
• D. x, x+y, (2y+1), (x-1)

Answer 1

The correct option is A

x, (x+y), 3y, x

The explanation for the correct option:

1. Electronic configuration of elements describes the distribution of electrons in the shells (orbitals) around the nucleus of an atom.
2. The shells are named K, L, M, N, O, and so on.
3. The number of electrons accommodated by each shell is-

K - 2 electrons, L- 8 electrons, M- 18 electrons, N- 32 electrons, O- 50 electrons and so on.

4. Now, the total number of electrons is determined from the atomic number of the element. As the atomic number of Zinc (Zn) is 30, hence the total number of electrons in zinc = 30.

5. Therefore, the electronic configuration of Zinc (Zn) is-

$$\begin{gathered} \mathrm{K}\mathrm{L}\mathrm{M}\mathrm{N} \\ 28182 \end{gathered}$$

6. Thus, number of electrons in K shell = number of electrons in N shell = x

7. Number of electrons in L shell = 8, and number of electrons in M shell = 18

$$\begin{gathered} (\mathrm{x}+\mathrm{y})=8 \\ \mathrm{y}=8-2=6 \end{gathered}$$

and $3\mathrm{y}=3\times 6=18\mathrm{electrons}$

8. Hence, the configuration that holds good for zinc is a) x, (x+y), 3y, x.

The explanation for the incorrect option:

B) As for Zinc (Zn, Atomic number = 30), the electronic configuration is- $$\begin{gathered} \mathrm{K}\mathrm{L}\mathrm{M}\mathrm{N} \\ 28182 \end{gathered}$$

Thus, the number of electrons in the K shell (= 2) = the number of electrons in the N shell (= 2). Hence, Option (b) does not satisfy this condition.

C) As per option c, the number of electrons in the L shell should be y = 8, and the number of electrons in the M shell should be 3y-1.

$$\begin{gathered} \mathrm{if}\mathrm{y}=8 \\ (3\mathrm{y}-1)=(3\times 8-1)=23\mathrm{electrons} \end{gathered}$$

It is impossible for the M shell to have 23 electrons. Thus, option c is incorrect.

D) For Zn, the electronic configuration is $$\begin{gathered} \mathrm{K}\mathrm{L}\mathrm{M}\mathrm{N} \\ 28182 \end{gathered}$$. The number of electrons in the K shell = number of electrons in the N shell. Option (d) does not satisfy this condition.

The correct option is (A).