Helium first was detected by observing an unidentified spectral line in a solar eclipse. Although helium is the second most abundant element in the universe, it is quite rare on earth! The gas is nonreactive, so it does not get bound up in compounds. Once it reaches it the atmosphere, helium is so light it can leak off into space. You encounter helium as a gas in party balloons. It is also used for cryogenic research and as an inert protective gas. A mixture of helium and oxygen is used as an atmosphere for divers to breathe.
Here are ten quick facts about the element Helium.
- The atomic number of helium is 2, meaning each atom of helium has two protons.
- Helium has the lowest melting point and boiling point of the elements, so it only exists as a gas except under extreme conditions.
- Helium is the second-lightest element.
- Helium is the second-most abundant element in the universe, though it is much less common on Earth.
- Helium is colorless, odorless, tasteless, non-toxic, and inert.
- Most helium is obtained by extracting it from natural gas.
- Helium is the second-least reactive noble gas (afterneon).
- Helium is monatomic under standard conditions.
- Inhaling helium temporarily changes the sound of a person's voice. Though helium is non-toxic, breathing it can result in asphyxiation due to oxygen deprivation.
- Evidence of helium's existence came from observation of a yellow spectral line from the sun.
