Hydrogen
Hydrogen is the simplest element there is and the most abundant in the universe, making up roughly three quarters of all baryonic matter.
Non-metals
Hydrogen, the halogens, oxygen and sulfur, nitrogen and phosphorus, carbon and silicon, boron, the noble gases and their compounds.
Material on this topic
Helium
Helium is the second most abundant element in the universe after hydrogen and one of the rarest on Earth.
Carbon
Carbon is the element the whole of organic chemistry and all known life rest on.
Nitrogen
Nitrogen makes up 78 % of the atmosphere by volume, and most organisms cannot use any of it.
Oxygen
Oxygen is the most abundant element in the Earth's crust, accounting for close to half its mass.
Chlorine
Chlorine is a yellow-green poisonous gas with a sharp smell, and at the same time one of the most sought-after products of the chemical industry.