Atomic number: 1

Symbol: H

Category: non-metal

Density at 25°C: gas 

Hydrogen is the first element. It is perhaps the most basic element of matter that can take place in a chemical reaction. It consists of a proton and optional neutron and an electron.


A discharge tube, an electrically excited sample of hydrogen. image:wikipedia

H by itself is still quite unstable and almost always naturally bound with another H atom to form H2 ( called a diatomic molecule)

Sometimes it was left by itself on the periodic table, now it sits on the top left because it tends to react rather like a reactive metal, just below it, that reactive element is lithium.

Use, natural applications or common combinations: 

  •  stars and nebula, gas giant planets
  • bound with oxygen to produce water, H2O

Basic characteristics:

  • Standard atomic weight: 1.008
  • Melting/freezing point: -259.14 °C
  • Boiling point: -252.87 °C
  • Radioactivity:
    •  isotopes: 3H half life: 12.32 years via beta - decay emitting an electron.