Atomic structure and the periodic table
50 exam-style questions with answers for 4.1 Atomic structure and the periodic table in AQA GCSE Chemistry (spec 8462). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, or read every question and answer below.
All 50 questions and answers
Question 1 · Spec 4.1.1.1 · Atoms and elements
What is an element? [1 mark]
Answer:A substance made of only one sort of atom.Question 2 · Spec 4.1.1.1 · Compounds
What is a compound? [2 marks]
Answer:Two or more elements chemically combined (1); in fixed proportions (1).Question 3 · Spec 4.1.1.1 · Equations
Balance the equation: Mg + O₂ → MgO. [1 mark]
Answer:2Mg + O₂ → 2MgO.Question 4 · Spec 4.1.1.1 · Compounds
Why can compounds only be separated by chemical reactions? [1 mark]
Answer:The elements are chemically bonded together.Question 5 · Spec 4.1.1.2 · Mixtures
What is a mixture? [1 mark]
Answer:Two or more elements or compounds not chemically combined together.Question 6 · Spec 4.1.1.2 · Separation
Name four physical processes used to separate mixtures. [2 marks]
Answer:Filtration and crystallisation (1); simple distillation, fractional distillation or chromatography (1).Question 7 · Spec 4.1.1.2 · Separation
Describe how to obtain pure salt crystals from rock salt. [3 marks]
Answer:Dissolve the rock salt in warm water (1); filter to remove the insoluble sand (1); evaporate some of the water and leave to crystallise (1).Question 8 · Spec 4.1.1.2 · Distillation
What is simple distillation used for? [1 mark]
Answer:To separate a liquid from a solution, for example water from salty water.Question 9 · Spec 4.1.1.3 · Atomic model
Describe the plum pudding model. [2 marks]
Answer:A ball of positive charge (1); with negative electrons embedded in it (1).Question 10 · Spec 4.1.1.3 · Atomic model
What did the alpha scattering experiment show? [2 marks]
Answer:The mass of an atom is concentrated at the centre (nucleus) (1); and the nucleus is charged (positive) (1).Question 11 · Spec 4.1.1.3 · Atomic model
What did James Chadwick show? [1 mark]
Answer:The existence of neutrons in the nucleus.Question 12 · Spec 4.1.1.4 · Subatomic particles
State the relative charges of protons, neutrons and electrons. [2 marks]
Answer:Proton +1 and electron −1 (1); neutron 0 (1).Question 13 · Spec 4.1.1.4 · Subatomic particles
Why do atoms have no overall charge? [1 mark]
Answer:They have equal numbers of protons and electrons.Question 14 · Spec 4.1.1.5 · Atomic size
What is the approximate radius of an atom? [1 mark]
Answer:0.1 nm (1 × 10⁻¹⁰ m).Question 15 · Spec 4.1.1.5 · Atomic mass
State the relative masses of a proton, neutron and electron. [2 marks]
Answer:Proton and neutron: 1 (1); electron: very small (about 1/1840) (1).Question 16 · Spec 4.1.1.5 · Atomic number
How many neutrons are in an atom of ³⁵Cl (atomic number 17)? [1 mark]
Answer:35 − 17 = 18.Question 17 · Spec 4.1.1.5 · Isotopes
What are isotopes? [2 marks]
Answer:Atoms of the same element with the same number of protons (1); but different numbers of neutrons (1).Question 18 · Spec 4.1.1.6 · Relative atomic mass
Chlorine is 75% ³⁵Cl and 25% ³⁷Cl. Calculate its relative atomic mass. [2 marks]
Answer:(35 × 75 + 37 × 25) ÷ 100 (1); = 35.5 (1).Question 19 · Spec 4.1.1.7 · Electronic structure
Write the electronic structure of sodium (atomic number 11). [1 mark]
Answer:2,8,1.Question 20 · Spec 4.1.1.7 · Electronic structure
Write the electronic structure of chlorine (atomic number 17). [1 mark]
Answer:2,8,7.Question 21 · Spec 4.1.2.1 · Periodic table
How are elements arranged in the modern periodic table? [1 mark]
Answer:In order of atomic (proton) number.Question 22 · Spec 4.1.2.1 · Periodic table
Why do elements in the same group have similar chemical properties? [1 mark]
Answer:They have the same number of electrons in their outer shell.Question 23 · Spec 4.1.2.2 · Mendeleev
State two things Mendeleev did when arranging his periodic table. [2 marks]
Answer:Left gaps for elements he thought had not been discovered (1); changed the order of some elements based on atomic weights to fit patterns in properties (1).Question 24 · Spec 4.1.2.2 · Mendeleev
Why was Mendeleev's table accepted? [1 mark]
Answer:Elements were later discovered that fitted the gaps and matched his predictions.Question 25 · Spec 4.1.2.2 · Isotopes
Why did isotopes explain why ordering by atomic weight was not always correct? [1 mark]
Answer:Isotopes of an element have different masses but the same atomic number, so atomic number is the right order.Question 26 · Spec 4.1.2.3 · Metals
Where are metals found in the periodic table? [1 mark]
Answer:To the left and towards the bottom.Question 27 · Spec 4.1.2.3 · Metals
Why do metals form positive ions? [1 mark]
Answer:They lose electrons from their outer shell.Question 28 · Spec 4.1.2.4 · Group 0
Why are the noble gases unreactive? [2 marks]
Answer:They have stable arrangements of electrons (1); a full outer shell (eight, or two for helium), so they do not easily gain or lose electrons (1).Question 29 · Spec 4.1.2.4 · Group 0
How do the boiling points of noble gases change down the group? [1 mark]
Answer:They increase with increasing relative atomic mass.Question 30 · Spec 4.1.2.5 · Group 1
Describe the reaction of sodium with water. [2 marks]
Answer:It fizzes, floats and moves around, melting into a ball (1); producing sodium hydroxide and hydrogen (1).Question 31 · Spec 4.1.2.5 · Group 1
Write the word equation for lithium reacting with water. [1 mark]
Answer:Lithium + water → lithium hydroxide + hydrogen.Question 32 · Spec 4.1.2.5 · Group 1
Explain why reactivity increases down Group 1. [3 marks]
Answer:The outer electron is further from the nucleus (1); there is more shielding by inner shells (1); so the outer electron is lost more easily (1).Question 33 · Spec 4.1.2.5 · Group 1
Write the formula of the compound formed between potassium and chlorine. [1 mark]
Answer:KCl.Question 34 · Spec 4.1.2.6 · Group 7
Describe how the melting and boiling points of halogens change down the group. [1 mark]
Answer:They increase as relative molecular mass increases.Question 35 · Spec 4.1.2.6 · Group 7
Explain why reactivity decreases down Group 7. [3 marks]
Answer:The outer shell is further from the nucleus (1); more shielding (1); so it is harder to gain an electron (1).Question 36 · Spec 4.1.2.6 · Displacement
What is seen when chlorine water is added to potassium bromide solution? [2 marks]
Answer:The solution turns orange (1); because chlorine is more reactive and displaces bromine (1).Question 37 · Spec 4.1.2.6 · Group 7
Describe chlorine at room temperature. [1 mark]
Answer:A green gas.Question 38 · Spec 4.1.2.6 · Displacement
Write a word equation for chlorine displacing iodine from sodium iodide. [1 mark]
Answer:Chlorine + sodium iodide → sodium chloride + iodine.Question 39 · Spec 4.1.3.1 · Transition metals
State two ways transition metals differ from Group 1 metals. [2 marks]
Answer:Any two from: higher melting points (except mercury) (1); higher densities (1); stronger and harder (1); much less reactive with water and oxygen (1).Question 40 · Spec 4.1.3.2 · Transition metals
State two typical properties of transition metal compounds. [2 marks]
Answer:Many form coloured compounds (1); many are useful as catalysts (1).Question 41 · Spec 4.1.3.2 · Transition metals
Why can transition metals form ions with different charges? [1 mark]
Answer:They can lose different numbers of electrons, for example Fe²⁺ and Fe³⁺.Question 42 · Spec 4.1.3.2 · Catalysts
Give one example of a transition metal used as a catalyst. [1 mark]
Answer:Iron in the Haber process (or nickel in the hydrogenation of oils).Question 43 · Spec 4.1.1.2 · Chromatography
What is chromatography used for? [1 mark]
Answer:To separate mixtures of soluble substances, such as dyes in an ink.Question 44 · Spec 4.1.1.2 · Fractional distillation
What is fractional distillation used for? [1 mark]
Answer:To separate a mixture of liquids with different boiling points.Question 45 · Spec 4.1.1.7 · Electronic structure
Describe the maximum number of electrons in the first three shells. [1 mark]
Answer:2, 8 and 8.Question 46 · Spec 4.1.2.1 · Periodic table
What does the period number tell you about an element's electrons? [1 mark]
Answer:The number of occupied electron shells.Question 47 · Spec 4.1.2.3 · Non-metals
Do non-metals form positive or negative ions? [1 mark]
Answer:Negative ions, by gaining electrons.Question 48 · Spec 4.1.1.1 · Symbols
How many atoms are in one molecule of H₂SO₄? [1 mark]
Answer:7 (2 H, 1 S, 4 O).Question 49 · Spec 4.1.2.5 · Group 1
Why are Group 1 metals stored in oil? [1 mark]
Answer:To stop them reacting with oxygen and water in the air.Question 50 · Spec 4.1.2.6 · Group 7
Why do halogens exist as diatomic molecules? [1 mark]
Answer:Two atoms share a pair of electrons to form a covalent bond, giving each a full outer shell.