| A | B |
|---|
| pure substance | matter that always has exactly the same composition; an element or a compound |
| element | a substance that cannot be broken down into simpler substances |
| atom | the smallest particle of an element |
| compound | a substance that is made from two or more simpler substances and can be broken down into those simpler substances |
| heterogeneous mixture | a type of mixture in which the parts of the mixture are noticeably different from one another |
| homogeneous mixture | a type of mixture in which the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another |
| solution | a mixture that forms when substances dissolve and form a homogeneous mixture |
| suspension | a heterogeneous mixture that seperates into layers over time |
| colloid | a mixture that contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension |
| physical property | any charecteristic of a material that can be observed or measured without changing the composition of the substances in the material |
| viscosity | the tendency of a liquid to keep from flowing; resistance to flowing |
| conductivity | a material's ability to allow heat or electric charges to flow |
| malleability | the ability of a solid to be hammered without shattering |
| melting point | the temperature at which a substance changes from solid to liquid |
| boiling point | the temperature at which a substance boils; the temperature at which vapor pressure is equal to atmospheric pressure |
| filtration | a process that separates materials based on size of their particles |
| distillation | a process that separates substances in a solution based on their boiling points |
| physical change | a change that occurs when some prooperties of a material change, but the substances in the material stay the same |
| chemical property | any property that produces a change in the composition of matter |
| flammability | a material's ability to burn in the presence of oxygen |
| reactivity | the propery that describes how readily a substance combines chemically with other substances |
| chemical changes | change that occurs when a substance reacts and forms one or more new substances |
| precipitate | a solid that forms and separates from a liquid mixture |
| solid | the state of matter in which materials have a definite shape and a definite volume |
| liquid | the state of matter in which a material has a definite volume but not a definite shape |
| gas | the state of matter in which a material has neither a definite shape nor a definite shape |
| kinetic energy | the energy an object has due to its motion |
| pressure | the result of a force distributed over an area |
| absolute zero | a temperature of 0 kelvins |
| Charles's law | the direct proportion of the volume of a gas to its temperature (in kelvins) if the pressure and the number of particles of the gas are constant |
| Boyle's law | the inverse variation of the volume of a gas with its pressure if the temperature and the number of particles are constant |
| phase change | a reversible physical change that occurs when a substance changes from one state of matter to another |
| endothermic | a description of a change in which a system absorbs energy from its surroundings |
| heat of fusion | the energy a substance must absorb in order to change from a solid to a liquid |
| exothermic | a description of a change in which a system releases energy to its surroundings |
| vaporization | the phase change in which a substance changes from a liquid into a gas |
| heat of vaporization | the energy a substance must absorb in order to change from a liquid to a gas |
| evaporation | the process that changes a substance from a liquid to a gas at temperatures below the substance's boiling point |
| vapor pressure | the pressure caussed by the collisions of particles in a vapor with the walls of a container |
| condensation | the phase change in which a substance changes from a gas or vapor to a liquid |
| sublimation | the phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first |
| deposition | the phase change in which a gas or vapor changes directly into a solid without first changing into a liquid |
| nucleus | the dense, positively changed mass located in the center of an atom |
| proton | a positively charged subatomic particle that is found in the nucleus of an atom |
| electron | a negatively charged subatomic particle that is found in the space outside the nucleus of an atom |
| neutron | a neutral subatomic particle that is found in the nucleus of an atom |
| atomic number | a unique number for each element that equals the number of protons in an atom of that element |
| mass number | the sum of the number of protons and neutrons in the nucleus of an atom |
| isotopes | atoms of a given element that have different numbers of neutrons and different mass numbers |
| energy levels | the possible energies that electrons in an atom can have |
| electon cloud | a visual model of the most likely locations for the electrons in an atom |
| orbital | a region of space around the nucleus where an electron is likely to be found |
| electron configuration | the arrangement of electrons in the orbitals of an atom |
| ground state | a state in which all the electrons in an atom have the lowest possible energies |
| periodic table | an arrangement of elements in columns, based on a set of properties that repeat from row to row |
| period | a row in a periodic table of elements |
| group | a column of elements in a periodic table |
| periodic law | the pattern of repeating properties displayed by elements in the periodic table |
| atomic mass unit (amu) | one twelfth the mass of a carbon-12 atom |
| metals | elements that are good conductors of heat and electricity |
| transition metals | elements that form a bridge between elements on the left and right sides of the periodic table |
| nonmetals | elements that are poor conductors of heat and electric current |
| metalloids | elements with properties that fall between those of metals and nonmetals |
| valence electron | an electron that is in the highest occupied energy level of an atom |
| alkali metals | the elements in Group 1A of the periodic table, not including hydrogen |
| alkaline earth metals | the elements in Group 2A of the periodic table |
| halogens | the elements in Group 7A of the periodic table |
| noble gases | the elements in Group 8A of the periodic table |
| electron dot diagram | a diagram of an atom, ion or molecule in which each dot represents a valence electron |
| ion | an atom or group of atoms that has a positive or negative charge |
| anion | an ion with a negative charge |
| cation | an ion with a positive charge |
| chemical bond | the force that holds atoms of ions togetheras a unit |
| ionic bond | the force that holds cations or anions together |
| chemical formula | notation that shows what elements a compound contains and the ratio of the atoms of ions of these elements in the compound |
| crystals | solids whose particles are arrangd in a lattice structure |
| electron affinity | the amount of attraction for electrons |
| ionization | process of removong electrons and forming cations |
