Question

Atomic size is the order of …………
A. ${10^{ - 8}}$cm
B. ${10^{ - 10}}$cm
C. ${10^{ - 13}}$cm
D. ${10^{ - 6}}$cm

Answer 1

Hint: Atomic size is defined as the distance between the centre of the nucleus of an atom and its outermost shell. It is determined with the help of X-ray diffraction technique.

Complete step by step answer:
Since the atomic radius of a chemical element is a measure of the size of its atoms and as we know the boundary of an atom is not well defined physical entity, no specific definition of atomic radius exists and it is difficult to measure the atomic size. There are some other reasons due to which we cannot determine the precise size of the atom.
1. It is not possible to isolate an individual atom for size determination.
2. The electron density around an atom is affected by the presence of neighbouring atoms. Hence the size of the atom changes somewhat in going from one condition to another.
However, As atoms pack up at a certain definite distance in solids we can get an idea about the approximate size of an atom and with the help of the X-ray diffraction technique the approximate size of an atom is of the order of ${10^{ - 8}}$ cm or ${10^{ - 10}}$ m or we can say the size of an atom is of the order of one-angstrom unit.

So, the correct answer is Option A .

Additional Information:
The other some factors on which atomic size depends are:
Nuclear charge
Number of orbits

Note:
The radius of the atomic nucleus is in the order of ${10^{ - 13}}$ cm or ${10^{ - 15}}$ m or one Fermi unit. Hence the radius of the nucleus is much smaller than the atomic radius.