The table shows the numbers of protons, neutrons and electrons in five particles, A, B, C, D and E.
| Particle | Number of protons | Number of neutrons | Number of electrons |
|---|---|---|---|
| A | 19 | 20 | 19 |
| B | 19 | 22 | 19 |
| C | 20 | 20 | 18 |
| D | 18 | 22 | 18 |
| E | 17 | 18 | 18 |
Which particle is a negative ion?
Which two particles are atoms of different isotopes of the same element?
Explain your answer.
Particles C and D have the same mass number.
Explain why C and D are not the same element.
Write the symbol for particle C. Include its mass number and its charge.
Use the Periodic Table.
Particle A loses one electron to form an ion.
State the charge and the mass number of the ion. Explain why the mass number does not change.
51 exam-style questions on OCR GCSE Chemistry 1.2 Atomic structure, covering 1.2.1 Development of the atomic model, 1.2.2 The nuclear model and the size of atoms, and 1.2.3 Subatomic particles in atoms and ions. Each one has a worked solution and a mark scheme showing where the marks go.