| A | B |
|---|
| nucleus | the tiny central core of an atom |
| proton | particle with a positive charge in the nucleus of an atom |
| neutron | neutral particle in the nucleus of an atom |
| electron | negatively charged particle which moves in the area around the nucleus of an atom |
| atomic number | the number of protons in an elements atom |
| atomic mass | the average mass of one atom of an elemen |
| valence electron | electrons farthest away from the nucleus and involved in the formation of chemical bonds |
| electron dot diagrams | a diagram using symbols and dots to represent the valence electrons of elements |
| atomic mass unit (amu) | unit used to measure the mass of particles in atoms |
| periodic table | table of elements in which the properties repeat in each period or row |
| group | vertical column of the periodic table |
| family | another name for a vertical column of the periodic table |
| period | horizontal row across the periodic table |
| malleable | capable of being pounded into shapes |
| ductile | capable of being pulled or drawn into a long wire |
| conductor | ability to transmit heat and electricity easily |
| magnetic | property of being attracted to magnets or capable of being made into a magnetic |
| corrosion | the gradual wearing away of a metal element due to chemical reaction |
| alkali metal | the most reactive elements which are group 1 metals |
| alkaline earth metal | highly reactive elements found in group 2 |
| transition metal | elements in groups 3 through 12 |
| lanthanide | rare earth elements placed below the periodic table and fit period 6 |
| actinide | rare earth elements placed below the periodic table and fit period 7 |
| nonmetal | elements to the right of the zigzag line in the periodic table |
| diatomic molecule | molecule composed of two atoms |
| halogen family | group 17 elements which have 7 valence electrons |
| noble gas | group 18 elements which have 8 valence electrons and are stable unreactive gases |
| metalloid | have some of the characteristics of metals and of nonmetals |
| semiconductor | substances that under some conditions carry electricity like metal and at under other conditions do not carry electricity |
| plasma | state of matter in which atoms are stripped of their electrons and nuclei are packed close together |
| neculear fusion | atomic nuclei combine to form a larger nucleus |
| supernova | tremendous explosion that breaks apart a massive star |
