1. Element- is a pure substance (homogeneous material) that broken down further (decomposed) by ordinary chemical means. (An element is made of only one kind of atom). Example: aluminum, hydrogen, calcium, mercury.

Elements are listed on the periodic table. Scientists have found 90 elements in nature, and about 20 more have been produced in the laboratory.

2. Compound- two or more elements chemically combined. (Note: if a sample of matter is made of atoms of two or more elements joined together, always in the same ratio, then that matter is a compound.)
Example: alcohol (C2H5OH), water (H2O), salt (NaCl), sugar C12H22O11) ammonia (NH3).

NOTE: When scientists refer to substances, they mean elements or compounds. A substance always has a definite composition.
 

Mixture- two or more elements or compounds that are blended without combining chemically. Each part of the matter in a mixture has its own identity (properties). Mixtures can be separated using physical or mechanical means.
Example: fabrics, vinegar, soil, rocks, rocks, milk, lemonade

Mixtures can be heterogeneous mixtures or homogeneous mixtures

    Heterogeneous mixtures- the substances in the kind of a mixture are not spread out  evenly. Example: a bottle of liquid salad dressing.

    Homogeneous mixtures- the substances are spread evenly throughout, a homogeneous mixture is called a solution. Example: vinegar (water and acetic acid are mixed evenly throughout). Other examples: sea water, soft drinks, glass
 

Solution- a homogeneous mixture in which one substance (the solute) is dissolved in another substance (the solvent). Example: salt water (Water, the solvent, plus salt, the solute, produces the solution of salty water.)

Suspension- a heterogeneous mixture in which the particles are large enough to be seen by a microscope or the unaided eye (eventually, they settle out of the mixture). Example: stirring a teaspoon of dirt in a glass of water.

Colloid- a mixture where the size of particles in the mixture are between those of a solution and a suspension. NOTE: The particles appear evenly distributed. Examples: fog, cheese, butter, jellies, whipped cream.