Which of the following statements about atomic radius in the modern periodic table is true?

i. Atomic radius increases from top to bottom.

ii. Atomic radius decreases from top to bottom.

iii. Atomic radius increases from left to right.

iv. Atomic radius decreases from left to right.

Atomic radius is defined as the distance of the outmost shell of the atom from the nucleus.

As we move down the group number of shells increases and therefore atomic radius increases from top to bottom. 

Along the period from left to right the effective nuclear charge increases . This leads to the stronger pulling of electrons from the outermost shell towards the nucleus; therefore, the atomic radius decreases from left to right.