Chemistry 5070 · O Level · Isotopes

Isotopes — practice question

The element chlorine has two isotopes, $^{35}_{17}\text{Cl}$ and $^{37}_{17}\text{Cl}$. In the Periodic Table, chlorine is shown as $^{35.5}_{17}\text{Cl}$. Which row gives the correct percentage of each isotope in a sample of chlorine found in nature?

  • A$25\%\;^{35}_{17}\text{Cl}$ and $75\%\;^{37}_{17}\text{Cl}$
  • B$40\%\;^{35}_{17}\text{Cl}$ and $60\%\;^{37}_{17}\text{Cl}$
  • C$50\%\;^{35}_{17}\text{Cl}$ and $50\%\;^{37}_{17}\text{Cl}$
  • D$75\%\;^{35}_{17}\text{Cl}$ and $25\%\;^{37}_{17}\text{Cl}$

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