Question

Which of the following matches is correct?
A.Last natural element- Uub
B.General electronic configuration of ${\text{IA}}$ group $- n{s^2}$
C.Inert gas lies in ${2^{nd}} - {6^{th}}$ group
D.Typical elements $- {3^{rd}}$ period elements.

Answer 1

We know that there are total $18$ groups (i.e. vertical lines) in the periodic table and total $7$ periods (i.e. horizontal lines) in the periodic table. And the elements of ${18^{th}}$ group, is known as inert gas.

Complete step by step solution:
Let us first talk about the natural elements.
Natural elements: They are those elements which are naturally occurring in the environment. Last naturally occurring element is uranium. The last element in the periodic table is $Uub$. So option A is incorrect.
General electronic configuration of ${\text{IA}}$ group $- n{s^1}$ where $n$ is the period number. They have one electron in the last s-subshell. Hence option b i.e. general electronic configuration of ${\text{IA}}$ group $- n{s^2}$ is incorrect.
We know that there are total $18$ groups (i.e. vertical lines) in the periodic table and total $7$ periods (i.e. horizontal lines) in the periodic table. And the elements of ${18^{th}}$ group, is known as inert gas. They are called inert gas because they have completely filled outer orbits. And they generally do not react with other elements. Hence option c i.e. inert gas lies in ${2^{nd}} - {6^{th}}$ group is also incorrect because inert gas element lies in ${18^{th}}$ group.
Typical elements: The third period elements i.e. sodium, magnesium, aluminium, silicon, phosphorus, sulphur, chlorine and argon, they are known as typical elements or representative elements. They are known as typical elements because the properties of these elements are characteristics to the whole group to which they belong. Hence option d i.e. typical elements $- {3^{rd}}$ period elements, is correct.

Hence option D i.e. typical elements $- {3^{rd}}$ period elements, is correct.

Note:
Atomic mass: The mass of an atom is known as atomic mass. It is represented by the symbol ${\text{A}}$.
Atomic number: It is defined as the number of protons in an atom. It is represented by the symbol $Z$.