Here's why:
* Weak intermolecular forces: Helium is a noble gas, meaning its atoms are very weakly attracted to each other. This is because they have a full outer shell of electrons and don't readily form bonds.
* Low atomic mass: Helium has the lowest atomic mass of all elements, which means its atoms are very light.
* Weak London dispersion forces: The only intermolecular forces present in helium are London dispersion forces, which are very weak and arise from temporary fluctuations in electron distribution.
These factors combine to result in a very low boiling point, meaning helium remains a gas at extremely low temperatures.
