Question

Which of the following elements would have the largest atomic radius?
A.Cl
B.F
C.Li
D.Ne
E.Na

Answer 1

Atomic radius is basically half the distance between adjacent atoms of the same element in a molecule. In general, the atomic radius decreases as we move from left to right in a period and it increases when we go down the group.

Complete step by step answer:
Atomic radius or atomic radii is basically the total distance from the nucleus of an atom to the outermost orbital of its electron. It is sometimes really difficult to determine the atomic radii because of the uncertainty in the position of the outermost electron.
Now, let’s consider the given options. As we go down the group, the number of shells increases, the atomic number increases and hence atomic radius also increases. Moreover, as we move along a period, the atomic number increases due to which the nuclear charge increases and hence the nuclear force of attraction also increases and thus atomic radius decreases.
Now, Li, F and Ne belong to the second period whereas Na and Cl belong to the third period. So basically, the third period will have a larger atomic radius than the second period because the third period lies below the second period. Moreover, Na lies to the left and Cl lies to the right of the periodic table and hence Na will have the largest atomic radius.

Hence, option E is correct.

Note: There are various types of radius with respect to the types of bonds. Some of them are Van Der Waals radius, ionic radius, metallic radius and covalent radius. Moreover, Heisenberg’s uncertainty principle can be used to get a precise measurement of the radius but it is not a completely correct option.