Hydrogen has three isotopes. Deuterium is used to make heavy water for some nuclear reactors.
| Isotope | Number of protons | Number of neutrons |
|---|---|---|
| hydrogen-1 | 1 | 0 |
| deuterium (hydrogen-2) | 1 | 1 |
| tritium (hydrogen-3) | 1 | 2 |
Give the mass number of tritium.
Explain why these three atoms are isotopes of the same element.
Explain why deuterium reacts with oxygen in the same way as hydrogen-1.
Heavy water has the formula D2O\mathrm{D_{2}O}D2O, where D is a deuterium atom. Calculate the relative formula mass of heavy water. The relative atomic mass of oxygen is 16.
The relative atomic mass of copper is 63.5. A student says this means that one atom of copper has a mass of 63.5. Explain why the student is wrong.
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.