front 1 the ratio of the weight of any volume of a substance to the weight of an equal volume of pure water at 4 degrees Celsius | back 1 specific gravity |
front 2 the time in which half the atoms of a radioactive material disintegrate | back 2 half-life |
front 3 a shiny, dense substance that easily conducts heat and electricity | back 3 metal |
front 4 the group 17 (Group VIIA) elements; consists of fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At) | back 4 halogens |
front 5 a group of related objects that work together to perform a function | back 5 system |
front 6 the spontaneous disintegration of the nucleus of an atom that results in the emission of radiation | back 6 radioactivity |
front 7 one of six elemental gasses that does not naturally react with other elements | back 7 noble gas |
front 8 the smallest unit of an element that has the properties of that element | back 8 atom |
front 9 a Russian scientist who organized and classified the elements based on similar physical and chemical properties; his work was the basis for the modern periodic table of the elements | back 9 Mendeleev |
front 10 the chart scientists use to organize and classify all the known elements | back 10 periodic table of elements |
front 11 the way parts are put together | back 11 structure |
front 12 a material with a particular chemical makeup | back 12 pure substance |
front 13 the path or orbit electrons follow around the nucleus of an atom | back 13 electron shell |
front 14 the number of protons in the nucleus of an atom | back 14 atomic number |
front 15 an element that is a greenish gas at room temperature | back 15 chlorine |
front 16 elements that lie between the metals and the nonmetals on the periodic table; these element exhibit both metallic and nonmetallic properties | back 16 metalloids |
front 17 one of the horizontal rows in the periodic table | back 17 period |
front 18 a generalization or rule that describes recurring facts or events in nature | back 18 law |
front 19 a pure substance that cannot be broken down into simpler substances by chemical reactions | back 19 element |
front 20 approximately equal to the number of protons and neutrons | back 20 atomic mass |
front 21 the chemical element consisting of one proton and one electron | back 21 hydrogen |
front 22 an element that makes up most of the air near Earth's surface | back 22 nitrogen |