TTUISD science 8A vocabulary flash cards

Question Answer
atomic number number of protons in the nucleus of an atom of a given element
electron negatively charged particle that exists in an electron cloud formation around an atom's nucleus
electron cloud region surrounding the nucleus of an atom, where electrons are most likely to be found
element substance that cannot be broken down into simpler substances
half life time it takes for half the atoms of a radioactive isotope to decay
isotope atoms of the same element that have different numbers of neutrons.
mass number the sum of neutrons and protons in the nucleus of an atom
neutron electrically neutral particle that has the same mass as a proton and is found in an atom's nucleus.
proton positively charged particle in the nucleus of an atom
radioactive decay process in which some isotopes break down into other isotopes, releasing energy and particles from the nucleus
transmutation the changing of one element into another through radioactive decay
catalyst substance that speeds up a chemical reaction but is not used up itself of permanetly changed
group family of elements in the periodic table that have similar physical or chemical properties
metal element that has luster, is melleable and ductile, and is a good conductor of heat and electricity
metalloid element element that shares some properties with metals and nonmetals
nonmetal element that is usually a gas or a brittle solid at room temperature and is a poor conductor of heat and electricity
period horizontal row of elements in the periodic table whose properties change gradually and predictably
representative element elements in groups 1&2 and 13-18 in the periodic table that include metals, metalloids, and non metals
semiconductor element that does not conduct electricity
synthetic elements elements tat do not occur naturally and are mad in laboratories
transition element elements in group 3-12 in the periodic table, all of which are metals
activation energy minimum amount of energy needed to start a chemical reaction
chemical equation shorthand form for writing what reactants are used and what products are formed in a chemical reactions; sometimes shows whether energy is produced or absorbed
chemical reaction process that produces chemical change, resulting in new substances that have properties different from those of the original substances
concentration the amount of substance present in a certain volume
endothermic reaction chemical reaction in which heat energy is absorbed
enzyme a protein that helps chemical reactions in organisms occur more quickly
exothermic reaction chemical reaction in which heat energy is released
inhibitor substance that slows down a chemical reaction, making the formation of a certain amount of product take longer
product substance that forms as a result of a chemical reaction
rate of reaction measure of how fast a chemical reaction occurs
reactant substance that exists before a chemical reaction begins
Archimedes' principle states that buoyant force on an object is equal to the weight of the fluid displaced bu the object
buoyant force upward force exerted on an object immersed in a fluid
condensation change of matter from a gas to a liquid state, such as water vapor changing into a liquid
density mass of an object divided by its volume
freezing change of matter from a liquid state to a solid state
gas matter that does not have a definite shape or volume; has particles that move at high speeds in all directions
heat movement of thermal energy from a substance at a higher temperature to a substance at a lower temperature to a substance at a lower temperature
liquid matter with a definite volume but no definite shape; can flow from one place to another
matter anything that takes up space and has matter
melting change of matter from a solid state to a liquid state
Pascal's principle states that when a force is applied to a confined fluid, an increase in pressure is transmitted equally to all parts of the fluid
pressure force exerted on a surface divided by the total area over which the force is exerted
solid matter with a definite shape and volume; has tightly packed particles that move mainly by vibrating
temperature measure of the average kinetic energy of the individual particles of a substance
vaporization change of matter from a liquid state to a gas
amplitude distance a wave rises above or falls below its normal level, which is related to the energy that the wave carries; in a transverse wave, this amount is one- half the distance between a crest and a troug
compressional wave a type of mechanical wave in which matter in the medium moves forward and backward in the same direction
diffraction bending of waves around a barrier
electromagnetic wave transverse waves that can travel through matter or space and are produced by the motion of electrically charged particles; include X- rays, ultraviolet waves, and visible light
frequency number of wavelengths that pass a given point in 1 second, measured in hertz
interference ability of two or more waves to combine and form a new wave when they overlap
mechanical wave a type of wave that can travel only through matter

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