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Which isotope below has 8 neutrons?

  1. 14C
  2. Oxygen-17
  3. 8Be
  4. Lithium-5
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The answer is A. This isotope of carbon has 8 neutrons and 6 protons.

Oxygen-17 has 9 neutrons and 8 protons, 8Be has 4 neutrons and 4 protons, and lithium-5 has 2 neutrons and 3 protons.

Two isotopes of oxygen are 18O and 16O. These two isotopes have different:

  1. Atomic numbers
  2. Charges
  3. Mass numbers
  4. Number of electrons
  5. Number of protons
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The correct answer is C. The isotopes have different mass numbers.

Which of the following have the same number of protons, but have different numbers of neutrons?

  1. 23Na and 24Mg
  2. 46Ca and 46Ti
  3. 7Li and 6Li
  4. 16O and 19F
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The correct answer is C.
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