Helium and Helium Atoms

**Symbol:** He

**Atomic number:** 2

**International title:** helium

**Relative Atomic Weight:** 4,003

**Information:** Helium is a colourless, light, single-gas, tasteless and odourless. Of all known gases, it has the lowest melting and boiling point. It is characterized by considerable chemical inertia (non-reactivity). In the fluid state, electrical current (superconductivity) is excellent and has very low viscosity (superfluidity). It is a non-metal.

**Use:** It is used to fill balloons and airships and as a refill (in combination with other rare gases) into lamps and laser tubes. Liquid helium is used as a refrigerant. It is also used as a packaging gas (E 939) in the food industry.

**Occurrence:** On earth, it is very rarely (rare gas) is present, especially in the higher levels of the atmosphere. On the other hand, it is the second most widespread element after hydrogen in space.