2He4.0026
Helium
Noble gasesColourless gases with full outer shells, so they hardly ever react.
1s²
- Atomic number
- 2
- Atomic mass
- 4.0026
- Protons
- 2
- Neutrons
- 2 (most common)
- Electrons
- 2
- Shells
- 2
- State at 25 °C
- Gas
- Position
- Group 18, period 1
Proton (+)Neutron (0)Electron (−)
Discovered byPierre Janssen and Norman Lockyer, 1868William Ramsay: 5 elementsPierre Janssen and Norman Lockyer: 1 element
Janssen spotted a new yellow line in sunlight while watching a solar eclipse from Guntur, India. Lockyer named it after the Greek Sun god Helios. It was found on Earth in 1895 by William Ramsay.
Did you know?
- It was discovered on the Sun before it was found on Earth.
- It almost never reacts with anything, because its only shell is full.
Where it's found
- Natural gas deposits
- The Sun and stars
What it's used for
- Party and weather balloons
- Cooling MRI scanner magnets
- Deep-sea diving gas mixtures
Try it
There's no safe home experiment for Helium. Explore it with the animated atom above instead.