Question

Which atom has the largest radius?
A) Neon B) Francium C) Helium D) Cesium

Answer 1

neon and helium both are group 18 elements

francium and caesium both are group 1 elements

Atomic radius of an atom increases as we go down the group and decreases as we go from left to right in a period

group 1 is present at the extreme left of the periodic table and group 18 is present at the extreme right of the periodic table

so according to this group 1 elements must have the highest atomic radius in the periodic table

but that's not the case noble gas elements are an exception

noble gas elements have the largest radius in the periodic table

as as helium is present above neon in the periodic table

the atomic radius of neon is a larger than helium

the answer is neon