Key Vocabulary Terms & People – Flashcards
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| Chemistry |
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| The study of the composition and properties of substances and the changes that such substances can undergo. |
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| Scientific Method |
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| Orderly adn systematic approach to gathering information in order to answer questions about the world. |
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| Observation |
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| Fact that is noticed either qualitatively or quantitatively, usually as an early part of the scientific method. |
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| Hypothesis |
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| Proposed, but unproved, explanation of observed facts. |
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| Experiment |
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| Carefully devised procedure for making observations and gathering data. |
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| Conclusion |
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| Judgment or opinion formed as a result of analyzing experimental data. |
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| Natural Law |
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| Description of a phenomenon that has been repeatedly and uniformly observed in nature. |
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| Theory |
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| Logical and time-tested explanation of a phenomenon that occurs in the natural world. |
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| Variable |
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| Factor being tested in an experiment |
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| Experimental Control |
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| Fasctor that ramains consstatn during an experiment and is compared with the variable. |
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| Metric System |
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| Deximal system of measurement used interenationallly |
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| Mass |
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| Quantity of matter in an object |
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| volume |
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| amount of space that an object occupies |
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| density |
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| mass of an object divided by its volume. |
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| Matter |
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| anything that has mass and volume |
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| solid |
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| state in which matter holds a definate shape and volume. |
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| Liquid |
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| state in which matter does not hold a definite shape but occupies a definite volume. |
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| Gas |
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| state in which matter has no definite shape or volume. |
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| Physical Property |
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| characteristic of a substance that can be ovserved without altering the identy of a substance. |
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| Chemical Property |
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| Characteristics of a substance that cannot be observed without altering the identy of a substance. |
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| Mixture |
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| blend of two or more pure substances that are not chemically combined. |
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| Homogeneous Mixture |
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| Mixture made up of uniformly intermingled particleas that therefore dose not contain visibly different parts. |
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| Heterogeneous Mixture |
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| Mixtuer in which the particles are nto uniformly intermingled and that therefore has visibly different parts. |
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| Atom |
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| Smallest particle of an element that retains teh chemical identity of the element. |
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| Atomic Theory of Matter |
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| theory proposed by John Dalton stating that elements are composed of atoms, all atoms of a given element are identical but different from atoms of other elements, atoms are neither created nor destroyed in a chemical reaction. |
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| Electron |
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| negatively charged particle within an atom |
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| Radioactivity |
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| spontaneous emission of radiation from an atom |
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| nucleus |
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| concentrated core of an atom, which contains protons and neutrons. |
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| Proton |
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| positively charged particle within the nucleus of an atom |
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| Neutron |
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| natural particle within the nucleus of an atom |
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| Atomic Number |
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| number of protons in the nucleus of an atom |
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| Ion |
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| a group that has a positive or negative charge because it has lost or gained electrons. |
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| isotope |
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| atom athat has the same number of protons as another atom, but different number of neutrons. |
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| Mass Number |
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| sum of the number of protons and neutrons in teh nucleus of a given atom |
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| atomic mass |
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| weighted average of the mass of the existing isotopes of an element. |
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| Electromagnetic Radiation |
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| form of energy consisting of waves made up of oscillations electric and magnetic fields at right angles to each other. |
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| Amplitude |
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| height of a wave measured from its orgin to its crest. |
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| Wavelength |
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| Distance between tow successive similar points on a wave |
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| frequency |
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| number of waves that pass a fiven point in a certain regions of an atom |
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| speed of light |
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| 3.00x10^8 ms |
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| Quantum |
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| discrete bit of energy; smallest unit of radiant energy that can be emitted or absorbed |
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| Photoelectric Effect |
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| Phenomenon in which light can be used to knock electrons out of a metal |
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| Photon |
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| quantum of electromagnetic energy |
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| Orbit |
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| term used to describe the probability of finding electrons in certain regions of an atom. |
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| sublevel |
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| division of principle energy levels in an atom |
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| electron configuration |
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| distribution of electrons among the orbitals of an atom |
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| Orbital diagram |
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| representation of an atom in which arrows in boxes are used to show the elextron configuration of an atom. |
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| Periodic Table |
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| Arrangement of elembents in order of their atomic numbers so that elements with similar electron configurations are located in teh same column. |
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| GroupFamily |
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| Verticle column ofthe periodic table |
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| Period |
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| Horizontal row of elements in the periodic table. |
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| Alkali Metal |
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| element in group 1A |
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| Alkali Earth Metal |
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| elements in group 2A |
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| Halogen |
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| reactive, non-metal in group 7A |
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| Noble Gas |
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| inactive element in group 8A |
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| Metal |
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| Element that typically has a high melting point, is ductile, malleable, shiny, and good conductor of heat and electricity. |
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| Non-Metal |
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| element that has a low melting point and a dull surface, breaks easily, is a poor conductor of heat and elextricity, and tends to gain elextrons in chemical reactions. |
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| SemimetalMetalloid |
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| element ahtt does not have a metallic properties; found on the right side fo the periodic table |
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| valence electron |
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| electrons in the outermost energy level of an atom |
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| electronegativity |
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| property of an element that indicates how strongly an atom of that element attracts electrons in a chemical bond |
