- Atomic Radius (Å)
Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among all the elements.
2
Atomic Number
4
Atomic Mass (u)
4.22
Boiling Point (K)
0.18
Density (solid: g/cm³, gas: g/liter)
0.49
Atomic Radius (Å)
0.28
Covalent Radius (Å)
24.59
First Ionization Energy (eV)
-48
Electron Affinity
1
Number of Shells
2
Electron Shell Occupations
5.19
Specific Heat (J/g)