| A | B |
|---|
| atomic number | the number ofprotons ina n atom's nucleus |
| average atomic mass | average mass of the mixture of its isotops |
| balance | used in laboratories to measure mass; it works b balancing a mass to be determined with a standard mass that is known |
| binary compound | a chmiscal compound composed of two elements |
| chemical bond | the force that holds together the atoms in a compound; chemical bonding occurs b/c atoms of most elements become more stable by losing, gaining, and sharing electrons |
| chemical change | the change of substances to different substances |
| chemical formula | a precise statement that tells which elements are ina compound and their ratios |
| chemical property | a characteristic of a substance that indicates whether it can undergo a specific chemical change |
| chemical reaction | a change in which one or more sumbstances are converted to different substances (the reactancts are changed into the products) |
| chemical symbol | a shorthand way to write the name of an element- Carbon=C |
| chemically stable | describes an atom whose outer energy level is completely filled w/ electrons OR follows the Octet Rule |
| chemically unstable | describes an atom whose outermost energy lecel is not filled w/ electrons so it seeks electrons from other atoms and thus forms compounds (doesn't follow octet rule) |
| colloid | a heterogeneous mixture containing tiny particles that never settle out |
| compound | substance made of the combineed atoms of two or more elements |
| constant | a factor that doesn't change in an experiment |
| control | a standard for comparison in an experiment |
| covalent bond | a type of chemical bond formed by atoms when they share electrons; covalent bonding produces molecules |
| density | mass per unit colume of a material(mass divided by volume) describes how tightly packed a substances molecules are {g/cm3} |
| dependent variable | factor whose value changes in an experiment |
| dot diagram | a diagram to reparesent electrons in the ou ter energy level of an atom, uses element symbol and dots |
| electron cloud | reigon where electrons are found surrounding the nucleus of an atom |
| electrons | negatively charged particles that move around the nucleus of an atom |
| element | substance in which all the atoms in a sample are alike |
| experiment | an organized procedure for testing a hypothesis. atypically has a control and dependent/independent variables |
| graduated cylinder | cylinder marked with a volume scarle, used in labs for measuring liquid volumes |
| group | in the periodic table, each of the 18 vertical columns of elements; each group is made up of elements w/ similar properties |
| halogens | highly active elements in periodic table group 17; have 7 electrons in their outer chells and readily combine w/ goupr 1 elements |
| heterogeneous mixture | a mixture in which different parts can be easily distinguished |
| homogeneous mixture | mixture in which different materials are blended evenly so that the mixture is the same throughout, also called a solution |
| hypothesis | testable prediction used to see how something works or to solve a problem |
| independent variable | factor adjusted to a different calue by the experimenter to see what effect it will have on teh dependedn variable |
| ion | a positively or negatively charged atom |
| ionic bond | a type of chemical vbond formed by the attraction between opposite charges of the ions in an ionic compound |
| ionization | the breaking apart of certain polar substances to form ions when dissolved in water |
| isotopes | atoms of the same element that have different numbers ofn eutrons |
| law of conservation of mass | law stating that matter is neither created nor destroyed during a chemical change |
| mass | measurememnt of the amount of matter in an object, its SI unit is a kilogram |
| mass number | sum of the number of protons and neutrons in an atoms nucleus |
| metalloids | elemnts having properties of both metals and nonmetals. metalloids are found along the stairstep line that separetes metlas from non metals |
| mixture | a materical made of elements or compounds stirred together but not combined chemically |
| neutron | atomic particle with no charge(neutral) taht is part of an atoms nucleus |
| nonmetals | elements that usally are gases or brittle solids ar room temperature, most do not conduct hear or electicity well. |
| nonpolar molecute | molecule that does not have oppositely charged ends |
| oxidation number | a positive of negatice number that indicates how many electrons an atom has lost, gained or shared when bonding with other atoms |
| period | a horizontal row in the periodic table |
| periodic table | a table of the elements arranced according to repeated changes in properties |
| physical change | a change in zize, shape, or color or state of matter |
| physical property | any caharcteristic of a material that can be observed without changeing the identity of the material itself |
| polar molecule | a molecule with opposite charges on each end |
| proton | atomic particle with a paositive charge that is part of an atoms nucleus |
| quarks | very small particles of matter that make up protons and neutrons |
| solution | homogeneous mizter containg particles so tine that they cannot be seen even with a microscope; particles in a solution dont settle and dont scatter light |
| standard | in measurement, exact quantity that everyone agrees to use as a basis of comparison |
| state of matter | any of the 4 conditions in which matter can exist, solid, liquid, gas, or plasma-depends on temp. |
| suspension | heterogeneous mixture containing a liquid in which larger particles eventually settle out |
| Tyndal effect | the scattering of light by particles in a mizter; this effect can be seen in all colloids |
| volume | amount of space occupied by ano object; volume units are found by combining other SI units of length |
