| A | B |
|---|
| atom | smallest particle of an element that still has the properties of that element |
| electron | subatomic particle with a negative charge and an atomic mass of nearly zero |
| nucleus | the atom's central region, consists of protons and neutrons; its diameter is nearly 100,000 smaller than the whole atom! |
| proton | positively charged particle found in the nucleus of the atom; a proton has a mass of 1 amu |
| neutron | particle in the nucleus of the atom with no charge; each neutron has a mass of 1 amu |
| periodic table of elements | the chart that shows all types of elements natural and man-made; it is organized by atomic number |
| metals | most elements -- tend to be shiny, malleable, ductile, and good conductors of heat and electricity. Examples are sodium, gold, copper. |
| nonmetals | A smaller group of elements -- their properties are usually the opposite of metals. Examples are carbon, nitrogen, oxygen. |
| metalloids | a small group of elements, also know as semi-conductors, that have some properties of both metals and nonmetals; example is silicon |
| pure substance | type of matter with one type of particle and consistent characteristic properties; compound or element |
| physical change | a change that does not alter the characteristic properties of a substance |
| chemical change | a change that does alter the characteristic properties of a substance |
| characteristic property | a physical or chemical property that can be used to identify a substance |
| compound | a pure substance made of two or more elements joined in a specific ratio by chemical bonds |
| mixture | two or more elements or compounds mixed together but not bonded chemically; no specific ratio |
| element | the simplest type of matter; all atoms are the same, a pure substance |
| molecule | two or more atoms joined by chemical bonds; also the smallest particle of a compound that still has the properties of that compound |
| homogenous mixture | mixture of substances where the 2 substances cannot be distinguished; smoothly mixed. |
| heterogenous mixture | mixture of substances where separate parts can be seen |
