Atomic NumberAtomic Number of Helium
Atomic Number of Helium is 2.
Chemical symbol for Helium is He. Number of protons in Helium is 2. Atomic weight of Helium is 4.002602 u or g/mol. Melting point of Helium is -272,2 °C and its the boiling point is -268,9 °C.
» Boiling Point » Melting Point » Abundant » State at STP » Discovery YearAbout Helium
The name of this element takes source from the Greek word meaning the Sun, primarily because it was discovered by astronomers to be present in the Sun prior to its being detected on our planet. Known as the second most common element in the Universe (though it is quite rare on our planet), Helium is one of the Noble gases, which is not reactive and does not mix with other elements to create other chemical compounds. The boiling point of Helium is the lowest of the ones in all other elements in the Periodic Table. Helium is lighter than air and is used in balloons, airships, and similar kind of devices. It is also a very effective cooling agent which is used in medicine and industry. As a mixture with neon, helium is used in common scanning devices in modern technology.
Uses of Helium
Helium which is the second lightest element after hydrogen is used to make airships such as blimps and weather balloons float in the air. It is also useful in scuba diving to prevent divers from getting too much oxygen. So divers use a mixture of helium and oxygen. Besides, you can see that helium is used in meteorology, in hard disk drives, and in rocket propulsion. Because helium is the coldest in liquid form, it is mostly used as a coolant in cryogenics too. There is also another use of helium as a carrier gas for gas chromatography.
Compounds with Helium
- Na2He = Disodium helide
- HeH+ = Helium Hydride Ion
Properties of Helium Element
| Atomic Number (Z) | 2 |
|---|---|
| Atomic Symbol | He |
| Group | 18 |
| Period | 1 |
| Atomic Weight | 4.002602 u |
| Density | 0.0001785 g/cm3 |
| Melting Point (K) | unknown |
| Melting Point (℃) | -272,2 °C |
| Boiling Point (K) | 4.22 K |
| Boiling Point (℃) | -268,9 °C |
| Heat Capacity | 5.193 J/g · K |
| Abundance | 0.008 mg/kg |
| State at STP | Gas |
| Occurrence | Primordial |
| Description | Noble gas |
| Electronegativity (Pauling) χ | no data |
| Ionization Energy (eV) | 24.58741 |
| Atomic Radius | 31pm |
| Covalent Radius | 32pm |
| Van der Waals Radius | 140 |
| Valence Electrons | 2 |
| Year of Discovery | 1895 |
| Discoverer | Ramsay and Cleve |