Question

The element with atomic number 30 is expected to be present in:
(A) IB group
(B) IA group
(C) IIA group
(D) IIB group

Answer 1

Hint: To solve this question we will be considering the electronic configuration of the element which has the atomic number 30. And then use the Aufbau’s principle for finding the group as well as the period of the given element.

Complete Solution :
So, we have been provided with an element whose atomic number is 30.
And we know that zinc has an atomic number equal to 30.
So, the element would be zinc,

- Now, we need to find the group to which it belongs, So, for that We will be considering the electronic configuration of zinc:
Zinc = $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^ {10}} $,
Now, according to Aufbau's principle the filled shell is $3{{d}^ {10}} $, so we can say that it lies in the d-block.

Now, we will be finding the period, So, for that we must know the highest numbered shell in the electronic configuration that is 4, So, we can say that it lies in period 4. Now, we will be finding to which group does zinc belong so, for finding the group we know that it depends on the block,

So, starting for s, p and d block:
For s block the group is the same as the number of electrons in the last shell, that is if we have $4{{s}^ {2}} $ in the last, the element is in the 2nd group.
Now, for p block it is the electrons in the last shell +10, that is if we have $2{{s}^{2}}2{{p}^ {6}} $ in the last of your subshell configuration, the element will lie in 2 + 6 + 10 = 18th group.
Now, for d block, let’s take an example of zinc: $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{10}}$,

- So, now take the valence shell that is $4{{s}^ {2}} $ and the d subshell that is $3{{d}^ {10}} $, add these two and we will get 12 which is the group of zinc.
So, the zinc belongs to the IIB group.
So, the correct answer is “Option D”.

Note: The Aufbau’s principle can be used to understand the location of electrons in an atom and their corresponding energy levels. Also, do find the period of zinc along with the group for finding the exact position of zinc in the periodic table.