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31 Cards in this Set
- Front
- Back
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atom |
the smallest particle into which an element can be divided and still be the same element |
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Democritus |
Greek philosopher who thought that you would eventually end up with a particle that could not be cut |
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Aristotle |
Greek philosopher who disagreed and didn't believe that such a particle could make up all substances found in nature |
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John Dalton |
The creator of the atom theory |
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The Atom Theory in 4 parts |
1. all matter is made up of atoms 2. atoms cannot be created or destroyed 3.all atoms of a certain element are identical 4.every substance is made up of atoms combined in certain ways |
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J.J. Thompson |
His experiments provided evidence that atoms are made up of even smaller particles also found that within the atom there is a negative charge |
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Electrons |
negatively charged particles |
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Ernest Rutherford |
Conducted an experiment to study the parts of an atom. Found nucleus the later found protons |
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nucleus |
a small,dense center that has a positive charge and is surrounded by moving electrons |
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Protons |
positively charged particles |
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Niels Bohr |
created model where electrons move around the nucleus in circular patterns |
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Neutrons |
particles that don't have any kind of a charge |
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Electron Cloud |
The area around the nucleus where electrons move around |
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Atomic Number |
number of protons in the nucleus of an atom is the atomic number of that atom |
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Isotopes |
atoms of the same element that have different numbers of neutrons |
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mass number |
total number of protons and neutrons in an atoms's nucleus |
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James Chadwick |
was Rutherford's student and discovered neutrons |
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Dmitri Mendeleev |
began thinking about how he could organize elements based on their properties to help him he made a set of element cards |
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Periodic table |
what Mendeleev arrangement created and got rearranged by British artist Henry Moseley |
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Henry Moseley |
determined number of protons in atoms of the elements, arranged them on the table in order of increasing number of protons, or atomic number |
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Metals |
elements that conduct heat and electricity well and are shiny |
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Malleable |
able to be formed into different shapes |
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Ductile |
they can be made into wires |
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Non metals |
poor conductors of heat and electricity and dull and britle |
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Metalloids |
Metalloids elements that have some properties of metals and of nonmetals |
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Chemical symbol |
abbreviation for the element's name |
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Chemical name |
names of the elements come from many sources |
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Average atomic mass |
atom is weighted average of the masses of all the naturally occurring isotopes of that element |
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Group or family |
each vertical column of elements on the periodic table top to bottom |
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period |
Each horizontal row of elements on the periodic table |
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valence electrons |
found in the outermost portion of the electron cloud of an atom |
