Comment by Wingman4l7
7 years ago
I was about to correct you and say that hydrogen is the smallest, but apparently, hydrogen's atomic radius is actually a bit bigger. Helium's radius is smaller due to the larger charge of the nucleus making for a tighter electron cloud.
I too had the same thought, and then thought maybe hydrogen molecule is being considered. Read up to see that hydrogen atom has bigger radius. TIL.
Hydrogen creates molecules H2.
Yup. Larger atomic radius due to less nuclear charge, and it's only stable in molecular form - H2.