Skip to content
Atomic number 2He

Helium

হিলিয়াম

  • Noble gas
  • Group 18
  • Period 1
  • Atomic mass 4.003 u
  • Gas

2p2n
Electrons per shell
2
Electron configuration
1s2
Nucleus
2 protons, 2 neutrons
Valence electrons
2
Speed1×
Group
18
Period
1
Block
s-block
Category
Noble gas
State at 25 °C
Gas