| A | B |
|---|
| alkali metals | Group IA |
| alkaline earth metals | Group IIA |
| atom | smallest representative particle of an element |
| atomic mass unit | 1/12 the mass of a carbon-12 atom |
| atomic number | the number of protons in the nucleus of an atom |
| cathode ray | a beam of electrons |
| Dalton | proposed the first modern atomic theory |
| Lavoisier | Law of Conservation of Mass |
| Law of Conservation of Mass | Matter is not created nor destroyed in a chemical reaction, atoms are rearranged. |
| electron | subatomic particle, -1 charge, orbits the nucleus |
| group | column on the periodic table |
| halogen | Group VIIA |
| inner transition metals | the actinides and lanthanides |
| isotopes | atoms of the same element that have different masses (same # of protons, different # of neutrons) |
| mass number | the number of protons and neutrons in the nucleus of an atom |
| metal | left side of the periodic table, loses electrons, shiny, ductile, malleable, ductile, conductive |
| metalloid | lies on the stair-step line, has both metallic and nonmetallic properties |
| neutron | subatomic particle, nucleus, zero charge |
| nobel gas | Group VIIIA, unreactive |
| nonmetal | right side of the stair-step line, gain or share electrons, brittle, insulating, not shiny |
| nucleus | small, dense, center of the atom containing most of the mass, has a positive charge |
| period | a row on the periodic table, the row number is equal to the number of energy levels |
| periodic law | the element on the periodic table have regularly repeating chemical and physical properties |
| periodic table | table that organizes elements in order of increasing atomic number, and by similar chemical and physical properties |
| proton | subatomic particle, +1 charge, in nucleus, identifies the element |
| representative elements | elements in groups IA-VIIIA |
| transition metals | the middle block of elements on the periodic table that is ten elements wide. |
