10 free IGCSE Chemistry Atoms, Elements & Compounds questions written in the style of Cambridge Chemistry papers: 5 multiple-choice and 5 structured, each with its answer and mark scheme. 4 of them are A* challenge questions, built to catch the mistakes strong students still make.
This topic covers Elements, compounds & mixtures, Atomic structure & the Periodic Table, Isotopes, Ions & ionic bonding, Covalent bonding & giant structures, Metallic bonding. Work through the questions below, then generate a full Atoms, Elements & Compounds paper with a fresh set every time.
Generate a full Atoms, Elements & Compounds paper →Two isotopes of the same element are compared.
1 They have the same number of protons.
2 They have the same number of neutrons.
3 They have the same chemical properties.
Which statements are correct?
Answer: B
Graphite and diamond are both forms of carbon.
1 Diamond conducts electricity because each atom forms four bonds.
2 Diamond has a low melting point because it is made of small molecules.
3 Graphite is soft because the forces between its layers are weak.
Which statements are correct?
Answer: D
Which property is NOT typical of metals?
Answer: C
What is the electronic configuration of the Al3+ ion?
Answer: D
Which particle has a relative charge of −1 and a very small mass?
Answer: B
Copper is used for electrical wiring and saucepan bases.
Explain why copper has a high melting point.
Suggest why copper is a good conductor of thermal energy.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | strong attraction between ions and electrons strong electrostatic attraction between the positive ions and the delocalised electrons B1 much energy needed to overcome B1 | 2 |
| (b) | delocalised electrons carry energy delocalised electrons move and carry energy through the metal B1 | 1 |
Magnesium has atomic number 12.
Draw/describe the electron arrangement of a magnesium atom.
Describe how the electronic configuration of magnesium changes when it forms an ion, and give the charge on the ion.
Explain why the noble gases are unreactive in terms of electronic configuration.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 2,8,2 2,8,2 B1 | 1 |
| (b) | loses 2 outer electrons; 2+ loses its two outer electrons to become 2,8 B1 forms Mg²⁺ B1 | 2 |
| (c) | full outer shell they have a full outer shell of electrons B1 | 1 |
This question is about the element bromine.
Bromine has two isotopes, bromine-79 and bromine-81. State what is meant by isotopes.
State the number of protons, neutrons and electrons in one atom of bromine-81.
Explain why the two isotopes have the same chemical properties.
A sample of bromine contains 50.7% bromine-79 and 49.3% bromine-81. Calculate the relative atomic mass of bromine. Give your answer to one decimal place.
Define relative atomic mass.
Give the electronic configuration of an atom of bromine and use it to predict the group of the element.
Explain, in terms of the particles in the nucleus, why the relative atomic mass of bromine is not a whole number.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | atoms of the same element with the same number of protons, different numbers of neutrons atoms of the same element / same proton number B1 different numbers of neutrons / nucleon numbers B1 | 2 |
| (b) | 35, 46, 35 protons 35 and electrons 35 B1 neutrons 46 B1 | 2 |
| (c) | same number of electrons in the outer shell same electronic configuration / same number of outer electrons B1 | 1 |
| (d) | 80.0 (79 × 50.7 + 81 × 49.3)/100 M1 80.0 A1 | 2 |
| (e) | average mass of the isotopes compared to 1/12 of a carbon-12 atom average mass of the isotopes of an element (weighted by abundance) B1 compared with 1/12 of the mass of an atom of carbon-12 B1 | 2 |
| (f) | 2,8,18,7; Group VII 2,8,18,7 B1 Group VII B1 | 2 |
| (g) | it is a weighted average of isotopes with different masses it is a weighted average of the masses of isotopes that have different numbers of neutrons B1 | 1 |
Ammonia, NH₃, is a covalent compound.
Describe the bonding in ammonia using a dot-and-cross description.
Explain why ammonia is a gas at room temperature.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 3 shared pairs, 1 lone pair three single covalent bonds (shared pairs) between N and H B1 one non-bonding pair on N B1 | 2 |
| (b) | weak intermolecular forces simple molecules B1 weak intermolecular forces need little energy to overcome B1 | 2 |
Chlorine has two isotopes, chlorine-35 and chlorine-37.
Define isotopes.
Explain why the isotopes have the same chemical properties.
Naturally occurring chlorine is 75% chlorine-35 and 25% chlorine-37. Calculate the relative atomic mass.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | same protons, different neutrons atoms of the same element / same number of protons B1 with different numbers of neutrons B1 | 2 |
| (b) | same electronic configuration they have the same number of electrons in the outer shell / same electronic configuration B1 | 1 |
| (c) | 35.5 (75 × 35 + 25 × 37) ÷ 100 C1 35.5 A1 | 2 |
In the 0620 syllabus, Atoms, Elements & Compounds covers Elements, compounds & mixtures, Atomic structure & the Periodic Table, Isotopes, Ions & ionic bonding, Covalent bonding & giant structures, Metallic bonding.
This page has 10 Atoms, Elements & Compounds questions with answers. For more, the free generator on mentorriyaz.in builds a new Atoms, Elements & Compounds paper with a full mark scheme each time you click.
Riyaz Shaikh has mentored IGCSE, IB and A Level students for 15+ years, one-on-one, online and in Mumbai. The hardest questions on this site are the ones he uses to find a student's weak points.
Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in