The word molecule is a diminutive of the Latin word "moles" which means mass, so molecule means "small mass". A molecule is the union or set of two or more atoms, which can be the same or different, if these atoms are separated it would change the properties of matter.
A molecule is a stable and electrically neutral system that is composed of the set of two or more atoms linked by chemical bonds, which are called covalent bonds. These atoms can be the same as in the case of hydrogen (H2) and oxygen (O2), which are diatonic molecules, or they can be formed by different atoms, as is the case with water (H2O), which is composed of two hydrogen atoms. and one of oxygen and methane gas (CH4) in whose molecule there are four hydrogen atoms linked to one of carbon.
The molecule is considered the smallest portion that can be obtained from matter so that it can retain its chemical properties. The main reason for molecules to form is that there are atoms that tend to reach a minimum energy condition and to achieve this it does so through covalent bonds with other atoms that present the same condition, this bond cannot be easily dissolved, and that is when a molecule is born.
In a substance, the molecules that compose them are not static, on the contrary, they are in constant movement, which is called molecular vibration, and this in turn can be flexion or tension.
