Look at the information about two isotopes of boron:
510Band 511B \text{ }^{10}_{5}\text{B} \quad \text{and} \quad \text{ }^{11}_{5}\text{B} 510Band 511BThe atomic number of boron is 5.
What is meant by mass number?
Explain why these two atoms of boron are isotopes.
Look at the information about other atoms and ions. Complete the table.
| Atom or ion | Atomic number | Mass number | Number of protons | Number of neutrons | Number of electrons | Electronic structure |
|---|---|---|---|---|---|---|
| N\text{N}N | 7 | 14 | .................... | 7 | 7 | .................... |
| P\text{P}P | 15 | 31 | 15 | .................... | .................... | 2.8.5 |
| S2−\text{S}^{2-}S2− | 16 | 32 | .................... | .................... | 18 | 2.8.8 |
| Na+\text{Na}^{+}Na+ | 11 | 23 | 11 | 12 | .................... | .................... |
The electronic structure of calcium is 2.8.8.2. The electronic structure of chlorine is 2.8.7. Calcium and chlorine react together to make calcium chloride.
Calcium chloride is an ionic compound.
Draw 'dot and cross' diagrams to show the ions made when calcium reacts with chlorine. Show the charges on the ions.
What is the formula of calcium chloride?
77 exam-style questions on OCR GCSE Chemistry Atomic structure. Each one has a worked solution and a mark scheme showing where the marks go.