The difference between solids, liquids, and gases at a molecular level is how much room the atoms have to move around. In solids, the atoms are packed closely together not leaving much room to move around, which gives them a definite shape and volume. The atoms in liquids have a little more room to move around and still have a definite volume. The atoms in gases have the most freedom with no definite shape or volume, so they are all separated.
They are all made of molecules and atoms, sometimes ions. In addition to this, liquids, gases and solids all have volume and shape.
By: Sol Santayana, Luz Esteban and Olivia Obligado