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| the smallest particle of an element that retains its identity in a chemical reaction |
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| the first theory to relate chemical changes to events at the atomic level |
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| a negatively charged subatomic particle |
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| a stream of electrons produced at the negative electrode (cathode) of a tube containing a gas at low pressure |
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| a positively charged subatomic particle found in the nucleus of an atom |
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| a subatomic particle with no charge and a mass of 1 amu; found in the nucleus of an atom |
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| the tiny, dense central portion of an atom, composed of protons and neutrons |
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| the number of protons in the nucleus of an element |
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| the total number of protons and neutrons in the nucleus of an atom |
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| atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons |
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| the quantitative makeup of an element's stable isotopes, in terms of percent abundance and mass |
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| a unit of mass equal to one twelfth the mass of a carbon-12 atom |
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| the weighted average of the masses of the isotopes of an element |
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| The way John Dalton described atoms in 1808 |
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| Discovered negatively-charged electrons by by J.J. Thomson in 1897 using electricity and charged plates |
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| Discovered that the atom is mostly empty space with all the positive charge in a very small central area called the nucleus by Ernest Rutherford in 1886 by using gold foil and a detecting film screen |
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| combining of atomic nuclei to produce a nucleus of greater mass. |
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| Splitting a heavy nucleus into two nuclei with smaller mass numbers |
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| consist of a stream of He particles.Can be stopped by a sheet of paper. |
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| consist of fast-moving electrons emitted from an unstable nucleus.Can be stopped by aluminum foil or thin piece of wood. |
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| High energy electromagnetic radiation.Is slowed by a lead shield and stopped by a concrete wall |
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| He developed and published a theory about how atoms look and behaved in 1808, and some of his theory is no longer accepted such as when he said atoms are indivisible and all atoms of a given element are the same. |
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| John Dalton described atoms as what? |
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| He discovered electrons by means of cathode ray experiment |
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| a negative electrode is called a |
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| a positive electrode is called a |
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| small pieces of metal which have electrical power running through them |
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