Answer:
Component having Smallest Atomic Size is 'Helium' having range approx. 31pm
I have seen that numerous individuals are noting with respect to hydrogen Atom however the genuine reason is along a period (left to right) the nuclear number increments while the valence electrons stay in a similar shell. Along these lines because of the expanding atomic charge (pulling electrons closer to the core) the radii of the iotas decline left to right.
Furthermore, as should be obvious from the table, Hydrogen and Helium are in a similar period so Helium having littlest size