| A | B |
|---|
| Nuclear Model of Atom | protons and neutron in dense central area, the nucleus, surrounded by freely orbiting electrons as proposed by Rutherford |
| Solar System Model of Atom | alternate explanation of nuclear model proposed by Rutherford emphasis on electrons freely orbiting nucleus |
| Energy Level Model of Atom | proposed by Neils Bohr modified Nuclear Model by explaining electrons were found on specific energy levels |
| valence electrons | electrons in an atoms outermost energy level |
| ion | a charged atom that has lost or gained an electron |
| Lewis electron-dot symbols | diagrams used to represent the valence electrons of an atom or ion |
| alkali metal | elements in group 1 with 1 valence electron and an oxidation number of +1 |
| alkaline earth metals | elements in group 1 with 2 valence electrons and an oxidation number of +2 |
| halogens | the most reactive group of non-metals, achieve a stable electron configuration by gaining an electron |
| noble gases | very stable becuase they have a full set of electrons in their otermost energy level |
| proton | an atomic particle that is positively charged |
| electron | the atomic particle that is negatively charged and moves around the outside of the nucleus |
| isotope | an atom of an element that have a different number of neutron in the nucleus |
| group | a column in the periodic table |
| nucleus | the part of an atom that contains protons and neutrons |
| period | a horizontal row in the periodic table |
| mass number | the sum of an atom's protons and neutrons |
| metalloids | elements that have properties of both metals and nonmetals |
| metals | located on the left side of the period table, they are good conductors of heat and electricity |
| nonmetals | elements on theright side of the periodic table, and are dull and brittle |
