Matter is anything that has mass and takes up space.
Matter can be a Pure Substance or an Mixture. A Pure Substance is a substance that is made up of only one type of atom. A Mixture is more than one element mixed. For example, helium, hydrogen, sulfur, would all be considered a pure substance. Rocks, muddy water, milk would be considered a mixture.
There are different types of mixtures, Homogenous which can be solutions(particles so small you cannot see), and Heterogenous which can be a suspension or colloid. Homogenous mixtures are a mixture that is uniform, or blended evenly through out. Heterogenous mixtures is a mixture you can see materials easily and doesn't mix evenly.
Homogenous mixtures are called solutions. Solutions are 2 substances that dissolve together into one. Homogenous mixtures are blended evenly, for example milk, its particles are small but don't settle at the bottom, they're mixed evenly through out. Tea or Lemonade would also be examples of a Homogenous mixture, they blend evenly throughout and don't settle at the bottom or separate.
In a Herterogenous Mixture its either a suspension or colloid. A Suspension is a mixture containing a liquid in which you can see the particles settle. A Colloid is a mixture that has larger particles than those in solutions but not heavy enough to settle. An example of a suspension is muddy pond water, the mud settles at the bottom. An example of a Colloid is milk, its particles are larger but cant settle
Pure Substances can be a element or a compound.
Elements are substances that are made up of only one type of atom. For example, Helium, Calcium, Iron would all be considered an element. Elements cant be connected together, meaning they cant combine because then they wouldn't be a Pure Substance.
Compounds are multiple substances combined together. Compounds are when 2 or more Elements combine and it creates a compound, for example NaCl which is Sodium Chloride, its 2 substances combined together. Other examples of a compound would be Water, which is H2O, It's 2 hydrogen and 1 oxygen combined making a compound.