Magnesium alloys are used in lightweight car wheels. Magnesium has atomic number 12. The table shows the isotopes in a sample of magnesium.
| Isotope | Percentage abundance (%) |
|---|---|
| magnesium-24 | 79.0 |
| magnesium-25 | 10.0 |
| magnesium-26 | 11.0 |
Give the number of neutrons in an atom of magnesium-25.
Calculate the relative atomic mass of magnesium in this sample. Give your answer to one decimal place.
Give the electronic configuration of an atom of magnesium-26.
A sample of magnesium from a meteorite has a relative atomic mass of 24.5. Suggest what this shows about the isotopes in the meteorite sample.
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.