A non-metal is a chemical element nonmetal which is neither a Halogène, nor a rare gas.

The non-metals include/understand the following elements thus:

• Hydrogen ₁H
• Carbon ₆C
• Nitrogen ₇N
• Oxygen ₈O
• Phosphorus ₁₅P
• Sulfur ₁₆S
• Selenium ₃₄Se

It should be noted that, put aside the Selenium which is a Oligo-élément, the non-metals consituent the majority of the atoms of the alive beings , even if the presence of others Atome S Ion S is also essential in less quantity such as the Chlore, the Calcium, the Fer, the Sodium and the Potassium.

The physical properties of the non-metals clearly differentiate them from metals: they badly conduct electricity (electric Conductivité, except carbon in its form graphite) and the heat (thermal Conductivité, except carbon in its forms graphite and… diamond); they are neither malleable, nor ductile.

It should be noted that in conditions of pressure and temperature extremes, a non-metal like hydrogen becomes metal (hydrogen with a pressure from approximately 300 GPa is completely monoatomic), which explains the important magnetic field of gas planet Jupiter.

The non-metals generally form connection S ionic with metals.