1.) Matter - anything that has mass and takes up space

2.) Atom - the basic unit of matter that cannot be broken down

3.) Proton - positively charged particles in an atom ( + )

4.) Neutron - uncharged particles in an atom ( 0 )

5.) Electron - negatively charged particles in an atom ( - )

6.) Nucleus - the center of an atom that holds the protons and neutrons

7.) Element - matter made up of one kind of atom

8.) Molecule - a substance that is made up of two or more atoms

9.) Compound - a substance that is made up of atoms of two or more different elements that are chemically combined

10.) Mixture - a combination of 2 or more things that are not chemically combined

11.) Periodic Table - a way to organize all of the elements by their properties and atomic number.

12.) Atomic number - the number of protons in an element

13.) Atomic Mass- the number of protons and neutrons in an element

14.) Chemical Symbol - the abbreviation that represents an element

15.) Pure substance - a substance that always has the same properties (such as appearance, melting point, & reactivity).

16.) Metal - elements that are shiny and are good conductors of heat and electricity.

17.) Nonmetal - elements that are dull in appearance and are poor conductors of heat and electricity.

18.) Metalloid - elements that have characteristics of metals and nonmetals

19.) Group (family)- the columns on the periodic table

20.) Period - rows on the periodic table that have similar properties

21.) Homogenous - Consisting of a mixture of the ‘same’ type of substance