Atom The “smallest piece” of matter that still keeps all the properties of the element (we will talk about properties later) All matter is composed of atoms

Atom Have we ever seen atoms? Yes – ever since the invention of the scanning tunneling electron microscope in 1981 by Nobel Laureates Gerd Binnig and Heinrich Rohrer Platinum atoms

Molecule Another “smallest piece” of matter – but are made of two or more atoms. All matter is composed of molecules

Molecule

Matter - Anything that has mass and takes up space

Pure Substance: is either an Element or a Compound

Element- Has only one kind of atom, found on the periodic table

Examples of Elements Anything on the periodic table H He ONe KAr NKr CXe CaRn

Compound - Substance with two or more kinds of atoms bound together

Example: Water The elements hydrogen and oxygen combine

Example : Salt The elements sodium and chloride combine (NaCl)

Mixture – is a impure substance made of two or more things mixed together Can be separated by physical means,

Homogeneous mixture- Evenly mixed mixture Sometimes called a solution

Examples of solutions Salt Water Rubbing Alcohol

Heterogeneous mixture- Unevenly mixed mixture *Different materials can be seen

Examples: Italian dressing, Concrete, Pizza

Colloids- A heterogeneous mixture that never settles and scatters light

Examples: gelatin, whipped cream

Examples: milk, fog

Suspension- A type of mixture in which visible particles settle

Examples: muddy water, Italian dressing, snow globes