| Terms |
Definitions |
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anions
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negative ions
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law
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a summary of observed behavior
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Thomson worked with cathode rays.
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True
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According to Dalton's atomic model, elements are composed of minute, indivisible particles called _____
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atoms
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negative ion. neutral atom _____ electrons
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GAINS
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This scientist created the Crookes tube which opened the door to the subatomic structure of the atom
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Crookes
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This scientist demonstrated that the atom contains neutrons
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Chadwick
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The nucleus does not contain what?
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electrons
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The proton and neutron are approximately the same mass.
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True
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In Rutherford's Gold Foil Experiment none of the alpha particles went through the gold foil.
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False
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The electron, the fundamental unit of charge, was discovered using _______ rays
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cathode
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Democritus (about 470-370 B.C.) thought that all forms of matter were composed of tiny indivisible particles (a.k.a....). Also, he held that atoms were in constant ______ and they ________ with one another
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atoms; motion; combined
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name the three subatomic particles
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electrons, protons, neutrons
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In reality, atoms can be __________ under special circumstances
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decomposed
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______ charges attract; like charges _____
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unlike; repel
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charge may be ___________ from one object to another, by contact or induction
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transferred
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The neutron was discovered by J.J Thomson.
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False
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The three ions of hydrogen are protium, deuterium, and tritium.
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False
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The atoms of the two different elements must have different mass numbers.
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False
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atomic mass
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average relative mass of the isotopes of that element compared to the atomic mass of carbon-12 (exactly 12.0000... amu)
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This scientist reasoned that an ion is an atom carrying a positive or negative charge
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Arrhenius
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In a neutral atom, the positive charge of the nucleus is exactly ______ by the negative electrons
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offset
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Sir William Crookes invented a type of tube.
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True
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Thomson model of the atom
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electrons are negatively charged particles embedded in the atomic sphere. The sphere also contains an equal number of protons, or positive charges
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In reality, atoms are composed of what type of particles?
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subatomic particles
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the less the distance between two charges, the greater the _____ __ __________ between unlike charges
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force of attraction
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A ____ ____________ can be used to determine the masses of individual atoms
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mass spectrometer
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Atom X has 9 protons 9 electrons and 10 neutrons. Atom Y has 10 protons 10 electrons and 9 neutrons. From this we can conclude that atom X and Y have the same mass.
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True
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mass number
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sum of the number of protons and the number of neutrons in the nucleus
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law of definite composition
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a compound always contains two or more elements chemically combined in a definite proportion by mass
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