| A | B |
|---|
| alkali metals | The elements in Group 1A of the periodic table, not including Hydrogen. |
| alkaline earth elements | The elements in Group 2A of the periodic table. |
| atom | The smallest particle of an element. |
| atomic number | A unique number for each element that equals the number of protons in an atom of that element. |
| brittle | A property of an element or compound that describes it being very fragile or easily broken. |
| coefficient | A number that appears before a formula in a chemical equation to show the relative proportions of each reactant and product. |
| conductivity | A material's ability to allow heat or electricity to flow. |
| ductile | The ability of metals to be pulled into wires. |
| electron | A negatively charged subatomic particle that is found in the space outside the nucleus of an atom. |
| element | A substance that cannot be broken down into simpler substances. |
| halogens | The elements in Group 7A of the periodic table. |
| ion | An atom or group of atoms that has a positive or negative charge. |
| isotope | Atoms of a given element that have different numbers of neutrons and different mass numbers. |
| luster | A property of metals that describes having a shining appearance. |
| malleable | The ability of a material to be hammered without shattering. |
| mass | The amount of matter in an object. |
| metals | An element that is a good conductor of heat and electric current. |
| non-metals | An element that is a poor conductor of heat and electric current. |
| molecule | A neutral group of atoms that are joined together by one or more covalent bonds. |
| neutron | A neutral subatomic particle that is found in the nucleus of an atom. |
| noble gases | The elements in Group 8A of the periodic table. |
| periodic table | An arrangement of elements in columns, based on a set of properties that repeat from row to row. |
| proton | A positively charged subatomic particle that is found in the nucleus of an atom. |
| shells | The region of space around a nucleus where an electron is likely to be found. |
| subscript | In a chemical equation these represent the numbers of atoms present in specific compounds of elements that are reactants or products. |
| transition elements | Elements that form a bridge between metals and nonmentals in the periodic table. |
