When two or more atoms combine they give rise to a molecule. A molecule can be made up of many atoms of the same element. There are 112 elements known to man, so can you imagine the different permutations and combinations of molecules...

Watch an animation of atoms and molecules colliding that shows how these particles combine during chemical reactions. Change levels of energy to see how reactions are affected.

The ideal gas law is an empirical law; it's a relationship between the pressure in a system of gases to the volume, the temperature, and the number of gas atoms/molecules in the system. This "law" is valid if the gas atoms/molecules are...

A covalent bond is formed between non metal atoms, which combine together by sharing electrons. Covalent compounds have no free electrons and no ions so they don't conduct electricity.