states of matter

 matter: anything that has mass and occupies space

atom: smallest unit of a matter

molecules: when atoms combine, they form molecules

particles: general term for atoms and molecules.

states of matter;

solids: have a definite shape and structure, have a fixed volume at a given temperature.  they increase in size when they are heated (expansion) and decrease in size when they are cooled. (contraction) 

the particles in solids are tightly packed together with a strong intermolecular force between them, they have an orderly and regular arrangement, forming a crystalline structure in many cases. they vibrate at a fixed place due to thermal energy, which means their focus is limited. least amount kf kinetic energy is present.

liquids: have a fixed volume at a given temperature, and will take the shape of the container they are poured in. 

the particles are close together, but not tightly packed. the intermolecular force is weaker than the one in solids but stronger than the one in gas. the arrangement of particles is not orderly nor fixed. the particles are in close proximity but are free to move past one another, leading to a more random arrangement. as the particles can move past and slide over each other, this allows them to flow and take the shape of their container. more kinetic energy than solid, less than gas.

gas: a gas neither has a fixed volume nor a fixed shape at a given temperature. it takes the shape of the container it is placed in. 

the particles are far apart from one another, and the intermolecular force is barely present. the particles have no fixed arrangement and are free to move in all directions. they spread out evenly to fill the entire volume of their container. they have a lot of kinetic energy, so, they collide with each other and the walls of their container.

changes of states:

solid to liquid > melting

liquid to solid > freezing

liquid to gas > evaporating (only the surface particles evaporate) and boiling (all the particles boil)

gas to liquid > condensation

solid to gas > sublimation