Question

If periodic table would have contained 10 periods, maximum elements in that periodic table would be:
A. 72
B. 190
C. 144
D. 290

Answer 1

Periodic table is a tabular display of the chemical elements, which are arranged by atomic numbers, electronic configuration and recurring chemical properties. There are seven rows known as periods, which have metals on the left and nonmetals on the right and 18 columns known as groups. These columns contain elements with similar chemical behaviors.

Formula used:
Even number of periods $= {\dfrac{{(n + 2)}}{2}^2}$

Complete step by step answer:
The periodic table is a representation of various elements.
A period is a horizontal row of the periodic table. There are seven periods with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons.
A group is a vertical column of the periodic table, based on the organization of the outer shell electrons. There are a total of eighteen groups. The periodic table is as shown:

Now, let us assume that the periodic table consists of 10 periods, then the number of elements would be:
n=10
Therefore, for even number of periods, according to the above formula:
We have,
10 Periods= $\dfrac{{{{(10 + 2)}^2}}}{2}$
=72
Therefore, the number of elements will be 72

Hence, option A is correct.

Note:
Dimitri Mendeleev is the father of the periodic table. In1869, he completed the first of his numerous periodic charts. It included 63 known elements arranged according to their increasing atomic weight. He also left spaces for as yet undiscovered elements for which he predicted the atomic weights.