Chlorine is used to kill bacteria in swimming pools. Chlorine has two isotopes. The table shows the abundance of each isotope in a sample of chlorine.
| Isotope | Mass number | Percentage abundance (%) |
|---|---|---|
| chlorine-35 | 35 | 75 |
| chlorine-37 | 37 | 25 |
Chlorine has atomic number 17. Give the number of neutrons in an atom of chlorine-37.
Calculate the relative atomic mass of chlorine. Use the equation:
relative atomic mass=(mass number of isotope 1×% abundance)+(mass number of isotope 2×% abundance)100\displaystyle \text{relative atomic mass} = \frac{(\text{mass number of isotope 1} \times \%\text{ abundance}) + (\text{mass number of isotope 2} \times \%\text{ abundance})}{100}relative atomic mass=100(mass number of isotope 1×% abundance)+(mass number of isotope 2×% abundance)
Give your answer to one decimal place.
Explain why the relative atomic mass of chlorine is not a whole number.
Lithium has two isotopes, lithium-6 and lithium-7. The relative atomic mass of lithium is 6.9. Deduce which isotope of lithium is more abundant. Give a reason for your answer.
46 exam-style questions on Edexcel GCSE Chemistry 2.1 Atomic structure, covering 2.1.1 Development of the atomic model, 2.1.2 Structure of the atom and subatomic particles, 2.1.3 Mass number, isotopes and relative atomic mass, and 2.1.4 Calculating relative atomic mass from isotopic abundance. Each one has a worked solution and a mark scheme showing where the marks go.