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38 Cards in this Set
- Front
- Back
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democritus |
greek philosopher that had a very simple idea of the atom |
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aristotle |
another greek philosopher who disagreed with democritus |
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atom |
the smallest particle into which an element cannot be divided and be the same element. basic unit of matter |
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dalton |
he created a theory that states that atoms make up matter |
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thomson |
found out about electrons |
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rutherford |
suggested that atoms have a small dense center called the nucleus. also found out about protons |
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bohr |
found out the new way electrons behave |
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nuetrons |
uncharged particles in the nucleus |
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electron cloud |
area in which electrons move around outside of the nucleus |
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proton mass |
1 amu |
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neutron mass |
close to 1 amu |
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atomic number |
number of protons in the nucleus of an atom |
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mass number |
total number of protons and neutrons in an atom's nucleus |
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mendeleev |
Russian chemist who began thinking of how to organize elements based on their properties |
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periodic table |
table that organized elements in ascending atomic mass |
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moseley |
edited original periodic table by increasing atomic number, or how many protons |
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chemical symbol |
abbreviation of the element's name |
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atomic number |
number of protons in the nucleus of an atom of that element |
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chemical name |
name of the element that comes from many different things |
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average atomic mass |
weighted average of the masses |
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metals |
elements that are shiny and conduct heat well and electricity |
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nonmetals |
poor conductors of heat and electricity |
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metalloids |
are elements that have some properties of metals and some others |
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group |
each vertical column of elements on the periodic table. sometimes called family |
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period |
each horizontal row of elements on the periodic table |
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chemical rection |
process in which atoms are rearranged to make new substances |
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chemical formula |
uses chemical symbols and numbers to represents a given substances |
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chemical equation |
uses chemical symbols and numbers to represent a given substance |
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reactants |
substances that participate in a chemical reaction. |
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products |
substances formed in a reaction |
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yields sign |
arrow that points from reactants to products |
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law of conservation of mass |
states that matter is neither created nor destroyed in ordinary physical and chemical changes |
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endothermc |
chem reaction that requires input of energy |
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exothermic |
chemical reaction that releases energy |
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law of conservation of energy |
states that energy cannot be created or destroyed |
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coefficient |
number placed in front of a chemical formula |
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subscript |
changing the subscript changes the identity of the compound |
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what changes the rate of reactions |
concentration, surface area, temp, and catalyst |
