| A | B |
|---|
| anion | negatively charged ion |
| atom | smallest unit of matter that retains the properties of an element |
| atomic mass | total mass of an atom, which is the mass in grams of one mole of the atom |
| atomic nucleus | atom’s central core, containing protons and neutrons |
| atomic number | number of protons in the nucleus of an atom |
| cation | on with a positive charge, produced by the loss of one or more electrons |
| chemical bond | ttraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms |
| chemical equilibrium | the point at which the rate of the forward reaction equals the rate of the reverse reaction |
| chemical reaction | rocess leading to chemical changes in matter |
| compound | substance consisting of two or more elements in a fixed ratio |
| covalent bond | bond in which two atoms share one or more pairs of valence electrons |
| dalton | measure of mass for atoms and subatomic particles |
| electron | subatomic particle with a single negative charge |
| electron shell | energy level represented as the distance of an electron from the nucleus of an atom |
| electronegativity | attraction of an atom for the electrons of a covalent bond |
| element | substance that cannot be broken down to any other substance |
| energy | capacity to do work (to move matter against an opposing force) |
| energy level | several different states of potential energy for electrons in an atom |
| hydrogen bond | the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule |
| ion | atom that has gained or lost electrons, thus acquiring a charge |
| ionic bond | chemical bond resulting from the attraction between oppositely charged ions |
| ionic compound | compound resulting from the formation of an ionic bond; also called a salt |
| isotope | One of several atomic forms of an element, each containing a different number of neutrons and thus differing in atomic mass |
| mass number | sum of the number of protons and neutrons in an atom’s nucleus |
| matter | Anything that takes up space and has mass |
| molecular formula | type of molecular notation indicating only the quantity of the constituent atoms |
| molecule | Two or more atoms held together by covalent bonds |
| neutron | electrically neutral particle, found in the nucleus of an atom |
| nonpolar covalent bond | covalent bond in which electrons are shared equall |
| orbital | three-dimensional space where an electron is found 90% of the time |
| periodic table of the elements | chart of the chemical elements, arranged in three rows, corresponding to the number of electron shells |
| polar covalent bond | bond between atoms that differ in electronegativity |
| potential energy | energy stored by matter as a result of its location or spatial arrangement |
| product | ending material in a chemical reaction |
| proton | subatomic particle with a single positive electrical charge |
| radioactive isotope | an atomic form of a chemical element that is unstable |
| reactant | starting material in a chemical reaction |
| salt | compound resulting from the formation of an ionic bond |
| structural formula | molecular notation in which the constituent atoms are joined by lines representing covalent bonds |
| trace element | element indispensable for life but required in extremely minute amounts |
| valence | bonding capacity of an atom, generally equal to the number of unpaired electrons |
| valence electron | electron in the outermost electron shell |
| valence shell | outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions |
| van der Waals interactions | Weak attractions between molecules or parts of molecules that are brought about by localized charge fluctuations |
