Matter can exist in one of three main states: solid, liquid, or gas. Solid matter is composed of tightly packed particles. A solid will retain its shape; the particles cannot move around. The liquid matter is made of more loosely packed particles. It will take the shape of its container. Particles can move about within a liquid but are packed densely enough to maintain volume. The gaseous matter is composed of particles packed so loosely that it has neither a defined shape nor a defined volume. A gas can be compressed. The temperature directly affects whether a substance exists as a solid, liquid, or gas. Generally, increasing the temperature turns solids into liquids and liquids into gases; reducing it turns gases into liquids and liquids into solids. A single particle does not have the properties of the material it is part of.
The properties of a substance are the properties of a huge number of particles together. A simple example is water. If you have a block of ice, you have solid water. Add heat (a form of energy), and the ice melts into liquid water you could drink (it has reached its melting point). Continue to apply heat, and the water will evaporate and turn into steam, which is water in a gaseous state (it has reached boiling point). This works backward, too. Gas can cool down (by losing energy), condense into liquid water, and cool down further into a solid. There is even a process called sublimation where a solid can turn straight into a gas when heat is applied.