Anything that has mass and takes up space

is made of molecules.

are made of atoms.

Particles are tightly packed together and DO NOT move past each other. They vibrate in place.

have a definite SHAPE

have a definite VOLUME

Disorder in the structures

Ordered Structures

positive and negative ions are held in the crystal arrangement by electrostatic attraction.

are made of molecules. There are strong bonds within the molecules (strong intramolecular forces) but weak attractions between the molecules (weak inter – molecular forces)

atoms occupy positions and they are joined by a network of covalent bonds