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22 Cards in this Set
- Front
- Back
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What is an atom?
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tiny particles that make up elements
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What is a nucleus?
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tiny central core of an atom and is composed of protons and neutrons
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What is a mass number?
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total number of protons and neutrons in an atom
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What are isotopes?
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atoms in the same element that have same # of protons but different #'s of neutrons
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What is an example of an isotope?
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15
E 7 |
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What is an example of a mass number?
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total number of protons and neutrons
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What is the number on the top of an isotopic notation?
ex:// 15 <--- E 7 |
the mass number
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What is the number on the bottom of an isotopic notation?
ex:// 15 E 7 <--- |
atomic number
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What is ANOTHER form of isotopic notation?
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neon-20
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What does amu stand for?
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Atomic Mass Unit
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What is amu?
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relative mass of a standard reference isotope
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What is atomic mass?
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weighted average mass of the atoms in a naturally occuring sample of the element
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How is atomic mass calculated?
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amu x abundance
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In a periodic table, what are columns called? Is this the energy level?
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group/family
no |
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In a periodic table, what are rows called? Is this the energy level?
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periods, yes
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In _______ Democritus discovered/described ______.
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~400 B.C.
~atomic philosophy-atoms r solid particles that r indivisible and indestructable |
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In ________ John Dalton discovered _______.
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~1803
~transformed Democritus ideas on atoms into a scientific theory |
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In ______ JJ Thompson discovered ________.
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~1897
~ electron |
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In ________ James Chadwick discovered ___________.
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~1891-1974
~confirmed existence of neutron |
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In __________ Eugene Goldstein discovered ________.
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~1850-1930
~ obsered cathode ray tube and found rays traveling opp. to cathode ray ---> composed of protons |
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Who discovered the plum pudding model?
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JJ Thompson
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Describe the plum pudding model?
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atom is fillled with positively charged material is distributed and electrons were evenly distributed.
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