Look at the information about two isotopes of lithium:
36Liand 37Li \text{ }^{6}_{3}\text{Li} \quad \text{and} \quad \text{ }^{7}_{3}\text{Li} 36Liand 37LiThe atomic number of lithium is 3.
What is meant by mass number?
Explain why these two atoms of lithium 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 |
|---|---|---|---|---|---|---|
| O\text{O}O | 8 | 16 | .................... | 8 | 8 | .................... |
| Al\text{Al}Al | 13 | 27 | 13 | .................... | .................... | 2.8.3 |
| Cl−\text{Cl}^-Cl− | 17 | 35 | .................... | .................... | 18 | 2.8.8 |
| Mg2+\text{Mg}^{2+}Mg2+ | 12 | 24 | 12 | 12 | .................... | .................... |
The electronic structure of magnesium is 2.8.2. The electronic structure of fluorine is 2.7. Magnesium and fluorine react together to make magnesium fluoride.
Magnesium fluoride is an ionic compound.
Draw 'dot and cross' diagrams to show the ions made when magnesium reacts with fluorine. Show the charges on the ions.
What is the formula of magnesium fluoride?
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.