Before they attempt to understand the properties of molecules, scientists first try to understand the atoms found in the molecules. This illustrates what?
the atoms of each element have different characteristics such as RAM (relative atomic mass) and atomic number and these characteristics affect what the shape and size of the molecule will be. Certain bonds have specific lengths and possible combinations depending on the characteristics of the atom. The number of electrons orbiting the nucleus and the arrangement of these affect the possible bonds with other atoms and the length and strength and angle of the bonds.