1- helium symbol is He, atomic number is 2 and its atomic weight is 4.003.
2- helium is a gas at room temperature.
3- helium is colourless, odourless and non toxic. Helium can be liquified, but has a very low condensation temperature.
4- helium is used to fill balloons, weather balloons and airships.
5- helium was discovered by Pierre Janssen, in 1868.
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