Hydrogen

Symbol: H
Atomic number: 1
Category: nonmetals
Group: 1
Period: 1
Block: s
Atomic weight: 1.00794 g/mol
Electrons per shell: 1
CAS number: 1333-74-0
Phase: gas
Density: 0.08988 g/l (in (0C, 101.325 kPa)
Melting point: 14.01 K (-259.14C, -434.45F)
Boiling point: 20.28 K (-252.87C, -423.17F)
Crystal structure: hexagonal
Oxidation states: 1, -1
Electronegativity: 2.20 (Pauling scale)
Name's origin: hydrogenes
Name's meaning: water creator as water is produced when hydrogen is burned
Facts:
- approximately 75% of the universe's elemental mass constitutes of hydrogen
- the lightest element of all
- hydrogen gas is highly flammable and burns at concentrations of 4% or above