Principle objective of this lecture is to present on why do Atoms Combine. There are several ways that atoms can combine. In one way, atoms are put together to form things called molecules. Just as human family members often have similar looks and traits, members of element families have similar chemical properties because they have the same number of electrons in their outer energy levels. Here also briefly focus on Noble Gases, Halogens, Alkali Metals and Electron Dot Diagrams.