Copyright © 2005 Ms. Broome Elements, Compounds and Mixtures Small, Medium, Large

Elements consists of only one kind of atom, cannot be broken down into a simpler type of matter by either physical or chemical means, and can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen). A molecule consists of two or more atoms of the same element, or different elements, that are chemically bound together. Each element is unique

Elements With over 100 elements, it is important to classify them in terms of their chemical properties (e.g. metal/non- metal). The Periodic Table is an advanced classification system.

Element Examples Elements and their atoms are represented by symbols. Argon, Ar Argon, Ar Lead, Pb Lead, Pb Gold, Au Gold, Au Aluminium, Al Aluminium, Al This is the element Argon

Compounds consists of atoms of two or more different elements bound together, can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means), has properties that are different from its component elements, and always contains the same ratio of its component atoms.

Compounds A compound is a substance formed when two or more elements are chemically joined. Water, salt, and sugar are examples of compounds. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of. Water molecule

Compound Examples Sodium (Na) + Chlorine (Cl) = Sodium Chloride

Mixtures consists of two or more different elements and/or compounds physically intermingled, can be separated into its components by physical means, and often retains many of the properties of its components.

Salad anyone? Mixtures are two or more substances that are mixed together but not chemically joined. A good example of a mixture is a salad. There are tomatoes, lettuce, cucumbers, and salad dressing all mixed together. No chemical reactions occur between the vegetables and the dressing. You can separate each of the vegetables from each other.

Dissolving Mixtures It is important to distinguish between three closely related terms solute, solvent, and solution. Solute – The substance that dissolves to form a solution Solute – The substance that dissolves to form a solution Solvent – The substance in which a solute dissolves Solvent – The substance in which a solute dissolves Solution – A mixture of one or more solutes dissolved in a solvent Solution – A mixture of one or more solutes dissolved in a solvent

Suspensions and Colloids SOLUTION (Liquid): Particles very small (0.1–1nm) do not settle out or scatter light, do not settle out or scatter light, can’t be separated by filtering can’t be separated by filtering Homogeneous mixture Homogeneous mixture –Ex. salt water, Kool-aid, soda pop, COLLOID: Particles larger (1–100 nm) do not settle out do not settle out do scatter light do scatter light can’t be separated by filtering can’t be separated by filtering Homogeneous mixture Homogeneous mixture –EX. Jello, milk SUSPENSION: Particles larger (>100 nm) will settle out will settle out do scatter light do scatter light can be separated by filtering can be separated by filtering heterogeneous mixture. heterogeneous mixture. –EX. salad dressing, muddy water nm= nanometer,1 billionth of a meter (10-9)