Question

In the periodic table, the atomic radius increases from left to right.
Reason:
The number of protons is increasing from left to right.
A.Both Assertion and Reason are True and the Reason is the correct explanation of the Assertion.
B.Both Assertion and Reason are True and the Reason is not the correct explanation of the Assertion.
C.Assertion is True but the Reason is False
D.Assertion is False, but the reason is True
E.Both assertion and reason are incorrect

Answer 1

Hint: As we go from left to right in a periodic table, the size of the atom reduces. And when we move from top to bottom the size of the atom increases. How far the last shell of electrons is away from the nucleus decides the atomic size. Farther the last shell is from the nucleus, the bigger the size of the particle.

Complete step by step answer:
When we look at the periodic table, we can see that as we go from left to right in the table the atoms are very small in appearance. This is because;
When we move from left to right through a periodic table, atomic radii reduce, which is because we move left to right in time because the number of valence electrons increases, and the attraction between the electron and the nucleus increases, meaning that the shell shrinks into the nucleus.
Let’s also understand the term atomic radius;
A calculation of the size of the atoms, typically they mean or normal distance from the center of the nucleus to the boundary of the surrounding electron shells is the atomic radius of a chemical substance.
The number of protons in the nucleus of the atom increases as we pass from left to right overtime on a periodic table as the atomic number increases. The larger the number of protons, the greater the force of attraction between the protons and the electrons, i.e. with greater force, the protons in the nucleus of the atom drag the electrons together. In brief, we can also assume that when we switch from left to right over a while, the nuclear charge rises. As a result, the last shell is pulled closer and the size of the atom reduces, and the atomic radii decrease.
From the above explanation, it is clear that the assertion is not correct, but the reason is correct.

Hence, for this question, option D is correct .

Note:
Note that when we move from left to right, all electrons are added to the same shell within a period of elements. Protons are, however, attached to the nucleus at the same time , making it more positively charged. The effect of increasing the number of protons is greater than that of increasing the number of electrons; thus, greater nuclear attraction occurs.