Question

Which of the following depicts the correct representation of the atomic radius of an atom?

(A) (i) and (ii)
(B) (ii) and (iii)
(C) (iii) and (iv)
(D) (i) and (iv)

Answer 1

We know that the atomic radius of an atom is basically the total distance from the center of the nucleus of an atom to its electron in the outermost orbital. It tells us about the size of an atom.

Complete step by step solution:
We all know that the atomic radius of an atom is basically the total distance from the center of the nucleus of an atom to its electron in the outermost orbital. It tells us about the size of an atom. The atomic radius generally decreases along a period because the atomic number increases which increases the number of protons but electrons are added to the same shell so due to increasing nuclear charge, the radius gradually contracts leading to the small size of the atom whereas moving down the group atomic radii increases as many energy levels are present and distance between a proton and electron increases. Also the electron shielding effect causes the attraction to decrease, so the radius increases and size is large.
In the given first diagram we can see that the electrons are present till the last shell but the distance between the nucleus and the first shell is shown which is wrong. In the second diagram we see that the electron is present in the second shell and the distance is also depicted correctly between the nucleus and the electron hence it is correct.
The third diagram shows the distance between the electrons present in the outermost shell and nucleus center, therefore it is also correct.
But in the last diagram the distance is shown between the outermost shell and adjacent shell which is wrong it tells nothing about the atomic radius, so it is also wrong.

Hence the correct answer is (B).

Note: Atomic radius plays an important role while explaining the behaviour of atoms or compounds. The noble gases do not form bonds so we can measure their van der waal forces. The smallest element is Helium and the largest element is Francium.