When elements form compounds, they create a new substance.For example, when two hydrogen molecules (H) and one oxygen molecule (O) combine they create water (H_2O) or when sodium (Na) and chlorine (Cl) form a compound they create Sodium Chloride (NaCl) or more commonly known as table salt.But we must ask how do these compounds stay together without splitting apart.The answer is a chemical bond.A chemical bond is an attraction between atoms by sharing electrons. There are three types of chemical bonds: Ionic, Covalent, and Polar covalent. Elements with low electro negativity usually form Ionic bonds, such as salt (NaCl) and usually one element gives up an entire shell to give to the other element. Elements with similar negativity form Covalent