which chemical element has the lowest boiling point?
Is it Helium(He) or is it Hydrogen(H)?
Hydrogen is lighter than Helium.
At its present form, this question is quite bad. I think you should've had a look at Wiki before asking this question. The boiling point of Hydrogen is around 20 K, while for Helium, it's around 4 K. I don't memorize these. But, I had a dirty look at Wiki. If you want a reason for why it has...
Helium has a stablest $1s$ orbital, which has somewhat lower energy. And, this makes it chemically inert towards other elements and to other Helium atoms, which is also the reason for its lowest boiling point.