Chemistry 4.1 & 4.2 Lesson Check – Flashcards
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What distinguishes the atoms of one element from the atoms of another?
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The number of protons are different. Protons are what make an element that particular element.
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How do isotopes of a given element differ from one another?
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They have different mass numbers and different numbers of neutrons.
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How is automatic mass calculated?
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For each isotope, multiply its mass by it's percent abundance (in decimal form - move the decimal two places to the left), and then add them all together. It should correspond to the atomic mass on the periodic table.
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What equation do you use to calculate the number of neutrons in an atom?
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Mass number - atomic number = neutrons
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How is atomic number different than the mass number?
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Atomic number is the number of protons in an atom. Mass number is the number of protons + neutrons in
an atom.
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What does the number represent in the isotope: platinum - 194?
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In this notation, the number is the mass number (the number of protons + neutrons)
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Why aren't atomic masses of elements usually whole numbers?
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Atomic mass is the weighted average of all masses of all of its isotopes.
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Which of argon's three isotopes is most abundant, Ar-36, Ar-38, or Ar-40?
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Ar-40. Because the atomic mass of argon on the periodic table is 39.948, that is closest to Ar-40, so that isotope must have the highest percentage of all three of the isotopes.
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List the protons, neutrons and electrons in each isotope, Li-6 and Li-7.
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Li-6 has 3 protons, 3 neutrons, and 3 electrons
Li-7 has 3 protons, 4 neutrons, and 3 electrons
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How does changing the value of a subscript change the chemical properties of an atom?
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The subscript designates the number of protons. Therefore, if you change the number of protons you
would change the identity of that atom into another element.
