| A | B |
|---|
| metallic bonds | the force of attraction that holds metals together; it consists of the attraction of free-floating valence electrons for positively charged metal ions |
| octet rule | atoms react by gaining or losing electrons so as to acquire the stable electrons structure of a noble gas, usually eight valence electrons |
| valence electrons | an electron in the highest occupied energy level of an atom |
| formula unit | the lowest whole number ratio of ions in an ionic compound |
| alloys | a mixture composed of two or more elemets, at least one of which is a metal |
| chemical formula | an expression that indicates the number and type of atoms present in the smallest representative unit |
| coordination number | the number of ions of opposite charge that surround each ion in a crystal |
| ionic bonds | the electrostatic attraction that binds oppositely charged ions together |
| ionic compounds | a compound composed of positive and negative ions |
| electron dot structure | a notation that depicts valence electrons around the atomic symbol of the element |
| ionization energy | the energy required to remove an electron form an atom in its gaseous state |
| metalloids | an element that tends to have properties that are similar to those of metals and nonmetals |
| periodic law | when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties |
| representative elements | an element in an "A" group in the periodic table |
| transition metal | elements of the Group B elements in which the highest occupied s sublevel and a nearby d sublevel generally contain electrons |
| inner transition metal | an elementin the lanthanide or actinide series; the highest occupied s sublevel and nearby f sublevel of its atoms generally contain electrons |
| ion | an aotm or group of atoms that has a positive and negative ions |
| metals | a class of elements that are good conductors of heat and electric current, they are ductile, malleable and shiny |
| noble gases | an element in Group 8A of the periodic table |
| nonmetals | an element that tends to be a poor conductor of heat and electric current |
| anion | any atom or group or atoms with a negative charge |
| cation | any atom or group of atoms with a positive charge |
| atomic radius | one-half the distance between the nuclei of two atoms of the same element when the atoms are joined |
| electronegativity | the ability of an atom to attract electrons when the atom is in a compound |
| halogens | a nonmetal in Group 7A of the periodic table |
| Hund's rule | electrons occupy orbitals of the same energy in a way that make the number or electrons with the same spin direction as large as possible |
| Pauli exclusion principle | an atomic orbital may describe at most two electrons, each with opposite spin direction |
| wavelength | the distance between adjacent crests of a wave |
| alkali metals | any metal in group 1A of the periodic table |
| alkalie earth metals | any metal in group 2A of the periodic table |
| Heisenberg uncertainty principle | it is impossible to know exactly both the velocity and the position of a particle at the same time |
| electromagnetic radiation | energy waves that travel in a vacuum |
| hertz | the unit of frequency, equal to one cycle per second |
| spectrum | wavelengths of visible light that are separated when a beam of light passes through a prism |
| electron configurations | the arrangement of electrons of an atom in its ground state into various orbitals around the nucei of atoms |
| atomic (line) emission spectrum | the pattern formed when light passes through a prism or diffraction grating to separate it into the different frequencies of light it contains |
| ground state | the lowest possible energy of an electron described by quantum mechanics |
| quantum mechanical model | the modern description, primarily mathematical, or the behavior of electrons in atoms |
| atomic orbital | a mathematical expressions describing the probability of finding an electron at vaious locations; usually represented by the region of space around the nucleus where there is a high probability of finding an electron |
| aufbau principal | the rule that electrons occupy the orbitals of lowest energy first |
| amplitude | the height of a wave's crest |
| energy levels | the specific energies an electron in an atom or other system can have |
| photons | a quantum of light |
| quantum | the amount of energy needed to move an electron from one energy level to another |
| frequency | the number of waves cycles that pass a given point per unit of time |
| cathode ray | a stream of electrons produced at the negative electrode of a tube containing a gas at low pressure |
| isotopes | atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons |
| mass number | the total number of protons and neutrons in the nucleus of an atom |
| periodic table | an arrangement of elements in which the elements are separated into groups |
| proton | a positively charged subatomic particle found in the nucleus of an atom |
| atomic mass | the weighted average of the masses of the isotopes of an element |
| atomic mass unit | a unit of mass equal to one-twelfth the mass of a carbon-12 atom |
| group | a vertical column of elements in the periodic table |
| period | a horizontal row of elements in the periodic table |
| atomic number | the number of protons in the nucleus of an atom of an element |
| atom | the smallest particle of an element that retains its identity in a chemical reaction |
| Dalton's atomic theory | the first theory to relate chemical changes to events at the atomic level |
| neutron | a subatomic particle with no charge and a mass of 1 amu; found in the nucleus of an atom |
| electron | a negatively charged subatomic particle |
| nucleus | the tiny, dense central portion of an atom, composed of protons and neutrons |
| density | the ratio of the mass of an object to its volume |
| dimensional analysis | a technique of problem-solving that uses the units that are part of a measurement to help solve the problem |
| energy | the capacity for doing work or producing heat |
| kilogram | the mass of 1 L of water as 4 degrees C; the base unit of mass |
| liter | the volume of a cube measuring 10 centimeters on each edge; the unit of volume |
| joule | the SI unit of energy; 4.184 J equal one calorie |
| temperature | a measure of the average kinetic energy of particles in matter |
| weight | a force that measures the pull of gravity on a given mass |
| Kelvin scale | the temperature scale in which te freezing point of water is 273 K and the boiling point is 373 K |
| conversion factor | a ratio of equivalent measurements used to convert a quantity from one unit to another |
| precision | describes the closeness, or reproducibility, of a set of measurements taken under the same condition |
| scientific notation | an expression of numbers in the form m x 10^n where m is equal to or greater than 1 and less than 10 and n is an interger. |
| Celsius scale | the temperature scale on which the freezing point of water is 0 degrees and the boiling point is 100 degrees |
| International System of Units | the revised version of the metric system, adopted by international agreement in 1960 |
| significant figures | all the digits that can be known precisely in ameasurement, plus a last estimated digit |
| meter | the base unit of length in SI |
| accuracy | the closeness of a measurement to the true value of what is being measured |
| gram | a metric mass unit equal to the mass of 1 cubic centimeter of water at 4 degrees Celsius |
| percent error | the percent that a measured value differs from the accepted value |
| calorie | the quantity of heat needed to raise the temperature of 1 g of pure water 1 degree C |
| absolute zero | the zero point on the Kelvin temperature scale |
| error | the difference between the accepted value and the experimental value |
| measurement | a quantitative description that includes both a number and a unit |
| accepted value | a quantity used by general agreement of the scientific community; the true value |
| experimental value | a quantitative value measured during an experiment |
| mass | a measure of the amount of matter that an object contains |
| mixture | a physical blend of two or more substances that are not chemically combined |
| phase | any part of a sample with uniform composition and properties |
| vapor | describes the gaseous state of a substance that is generally a liquid or solid at room temperature |
| volume | a measure of the space occupied by a sample of matter |
| solid | a form of matter that has a definite shape and volume |
| solution | a homogeneous mixture |
| liquid | a form of matter that flows, has fixed volume and an indefinite shape |
| filtration | a process that separates a solid from the liquid in a heterogeneous mixture |
| substance | matter that has a uniform and definite composition |
| reactant | a sustance present at the start of a reaction |
| law of conservation of mass | in any physical change or chemical reaction, mass is conserved; mass can neither be created or destroyed |
| compound | a substance that contains two or more elements chemically combined in a fixed proportion |
| distillation | a process used to separate dissolved solids fro a liquid, which is boiled to produce a vapor that is then condensed into a liquid |
| element | the simplest for of matter that has a unique set of properties |
| precipitate | a solid that forms and settles out of a liquid mixture |
| chemical symbol | a one or two-letter representation of an element |
| intensive property | depends on the type of matter in a sample, not the amount. |
| product | a substance produced in a chemical reaction |
| extensive property | depends on the amount of matter in a sample, not the type |
| chemical property | the ability of a substance to undergo specific chemical change |
| chemical reaction | a chane in which one or ore reactants change into one or more products; characterized by the breaking of bonds in reactants and the formation of bonds in products |
| heterogeneous mixture | a mixture that is not uniform in composition |
| homogeneous mixture | a mixture that is uniform in compostion |
| physical property | a quality or condition of a substance that can be observed or measured without changing the substance's composition |
| scientific law | a concise statement that summerizes the results of many observations and experiments |
| matter | anything that has mass and occupies space |
| chemical change | a change that produces matter with a different composition than the original matter |
| gas | a form of matter that takes the shape and volume of its container; no definite shape or volume |
| physical change | a change during which some properties of a material change, but the composition of the material does not change |
| applied chemistry | research that is directed toward a practical goal or application |
| biochemistry | the areas of chemistry that focus on processes that take place in organisms |
| macroscopic | describes the world of objects that are large enough to see with the unaided eye |
| pure chemistry | the pursuit of chemical knowledge for its own sake |
| responding variable | the variable tha is observed during an experiment: also called dependent variable |
| organic chemistry | the study of compounds containing carbon |
| scientific method | a logical systematic approach to the solutions of a scientific problem |
| manipulated variable | the variable that is changed duirng an experiment; also called independent variables |
| biotechnology | the field that applies science to the production of biological products or process |
| microscopic | describes the world of objects that can be seen only under magnification |
| chemistry | the study of the composition of matter and the changes that matter undergoes |
| observation | information obtained through the senses; often involves a measurement |
| technology | the means by which a society provides its members with those things needed and desired |
| pollutant | a material found in air, water, or soil that is harmful to humans and other organisms |
| inorganic chemistry | the study of substances that, in general, do not contain carbon |
| analytical chemistry | the area of study that focuses on the composition of matter. |
| hypothesis | a proposed explanation for an observation |
| physical chemistry | the area of study that deals with the mechanism, the rate, and the energy transfer that occurs when matter undergoes a change. |
| theory | a well tested explanation for a broad set of observations |
| experiment | a repeatable procedure that is used to test a hypothesis |
| bonding orbital | a molecular orbital that can be occupied by two electrons of a covalent bond |
| covalent bond | a bond formed by the sharing of electrons between atoms |
| coodinate covalent bond | a covalent bond in which one atom contributes both bonding electrons |
| diatomic molecule | a molecule consisting of two atoms |
| polyatomic ion | a tightly bound group of atoms that behaves as a unit and has a postitive or negative charge |
