The table shows the numbers of particles in six species, A to F. Some are atoms and some are ions.
| Species | Protons | Neutrons | Electrons |
|---|---|---|---|
| A | 17 | 18 | 17 |
| B | 17 | 20 | 17 |
| C | 18 | 22 | 18 |
| D | 19 | 20 | 18 |
| E | 20 | 20 | 20 |
| F | 16 | 16 | 18 |
Give the mass number of C.
Give the letters of two atoms that are isotopes of the same element. Explain your answer.
C and E have the same mass number. Explain why they are atoms of different elements.
D and F are ions. Use the periodic table to give the symbol and charge of each ion.
Species G has 17 protons, 18 neutrons and 18 electrons. A student says that G is an isotope of A. Explain whether the student is correct, and give the symbol and charge of G.
Chlorine gas is made of Cl2\mathrm{Cl_{2}}Cl2 molecules. Chlorine contains only atoms of A and B. About 75% of the atoms are A. Deduce the relative masses of all the different Cl2\mathrm{Cl_{2}}Cl2 molecules that can form, and state which of these molecules is the least common. Give a reason.
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.