Lesson 4A.1

4A.1 Group 1 and 2 trends, reactions and flame colours Quiz: Pearson Edexcel Chemistry, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4A.1, Group 1 and 2 trends, reactions and flame colours: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 4: Inorganic Chemistry and the Periodic Table, written with Revision Ninja.

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The 20 questions

  1. Why does first ionisation energy decrease down Group 2?

    • Nuclear charge decreases down the group, so the outer electrons are held less tightly by the atoms overall
    • The outer electrons move into lower-energy sub-shells as the group is descended, which makes them easier to remove
    • Group 2 atoms gain neutrons as the group is descended, and these neutrons weaken the attraction to the electrons
    • Atoms get larger and shielding increases, so the outer electron is held less strongly

  2. Why does reactivity of Group 2 elements increase down the group?

    • Atoms gain electrons more easily down the group, because the outer shell becomes less full and more reactive
    • Atoms become smaller and more electronegative as the group is descended, which makes them more reactive
    • Atoms lose outer electrons more easily, because the ionisation energy falls
    • Atoms have fewer electrons in their outer shell as the group is descended, which makes them more reactive overall

  3. What is the product when magnesium burns in oxygen?

    • Magnesium oxide, MgO
    • Magnesium hydroxide, Mg(OH)2
    • Magnesium carbonate, MgCO3
    • Magnesium peroxide, MgO2

  4. Which equation shows the reaction of calcium with water?

    • Ca + H2O -> CaO + H2, which gives calcium oxide and hydrogen but is not balanced for the water used
    • Ca + H2O -> CaCO3 + H2, which gives calcium carbonate and hydrogen in the presence of water
    • Ca + 2H2O -> Ca(OH)2 + H2
    • Ca + 2H2O -> CaO2 + 2H2, which gives a peroxide product that is not the usual product of the reaction

  5. What is formed when calcium oxide reacts with water?

    • Calcium peroxide, which is an acidic compound that releases oxygen when it dissolves in water
    • Calcium hydroxide, which is an alkaline solution
    • Calcium chloride, which is neutral in solution and does not change the pH of the water at all
    • Calcium carbonate, which is insoluble in water and forms a white precipitate in the solution

  6. Which is the correct equation for magnesium oxide reacting with dilute hydrochloric acid?

    • MgO + 2HCl -> MgCl2 + H2
    • MgO + 2HCl -> MgCl2 + H2O
    • MgO + HCl -> MgCl + H2O
    • MgO + HCl -> MgCl2 + H2O2

  7. Which Group 2 hydroxide is the most soluble in water?

    • Barium hydroxide
    • Beryllium hydroxide
    • Magnesium hydroxide
    • Calcium hydroxide

  8. How does the solubility of Group 2 sulfates change down the group?

    • It is the same for all sulfates in the group, so none of them is more soluble than another
    • It increases, so barium sulfate is the most soluble of the Group 2 sulfates in water at room temperature
    • It increases only for the Group 1 sulfates, while the Group 2 sulfates stay equally insoluble
    • It decreases, so barium sulfate is the least soluble

  9. Why does thermal stability of Group 2 carbonates increase down the group?

    • Larger cations have more protons that stabilise the carbonate ion, which makes decomposition harder to start
    • Smaller cations polarise the carbonate ion less, so the carbonate is more easily decomposed by heat
    • Larger cations polarise the carbonate ion less, so it is less easily decomposed
    • Group 2 carbonates become more covalent down the group, which makes them harder to decompose on heating

  10. What is the product of heating magnesium carbonate?

    • Magnesium oxide and carbon dioxide
    • Magnesium hydroxide and carbon dioxide
    • Magnesium chloride and water
    • Magnesium oxide and hydrogen

  11. Which equation shows the thermal decomposition of calcium carbonate?

    • CaCO3 -> Ca(OH)2 + CO2
    • CaCO3 -> Ca + CO2 + O2
    • CaCO3 -> CaO + CO2
    • CaCO3 -> CaO2 + CO

  12. Which flame colour is characteristic of barium compounds?

    • Lilac, which is the characteristic flame colour produced by potassium compounds in the flame
    • Apple green
    • Crimson, which is the characteristic colour of lithium compounds in a flame test
    • Brick red, which is the colour produced by calcium compounds in a Bunsen flame

  13. Which Group 1 metal gives a yellow-orange flame colour?

    • Sodium
    • Lithium
    • Potassium
    • Caesium

  14. Why do Group 1 and 2 compounds produce characteristic flame colours?

    • The metal burns in the flame and gives off a coloured gas that carries the characteristic colour
    • Electrons are excited and drop back to lower energy levels, emitting visible light of specific wavelengths
    • Water is decomposed in the flame to give a coloured gas that tints the flame in a characteristic way
    • Ions absorb all visible light, so the flame looks coloured where the ions are present in the sample

  15. Which Group 2 ion gives a brick red flame?

    • Magnesium, Mg2+
    • Barium, Ba2+
    • Calcium, Ca2+
    • Beryllium, Be2+

  16. Which observation shows that the reactivity of Group 2 metals increases down the group?

    • Calcium reacts vigorously with cold water but magnesium reacts only slowly with cold water
    • Magnesium reacts faster with cold water than calcium does, which shows that reactivity falls down the group
    • All Group 2 metals react equally with cold water, so the reactivity does not change down the group
    • Barium reacts with water less vigorously than magnesium does, which is consistent with a fall in reactivity

  17. Which product forms when magnesium reacts with chlorine?

    • Magnesium hypochlorite, Mg(ClO)2
    • Magnesium chlorate, Mg(ClO3)2
    • Magnesium chloride, MgCl2
    • Magnesium dichloride oxide, MgClO

  18. Why does the solubility of Group 2 hydroxides increase down the group?

    • Lattice energy falls more than the hydration energy as the cation gets larger
    • The hydroxides become covalent down the group, so they dissolve more readily in the water solvent
    • Hydroxide ions get larger down the group, which makes the hydroxides more soluble in the water solution
    • Hydration energy falls faster than lattice energy as the group is descended, so the hydroxides dissolve less

  19. Which Group 2 nitrate on heating gives a metal oxide, nitrogen dioxide and oxygen?

    • Barium carbonate
    • Calcium nitrate
    • Magnesium chloride
    • Lithium nitrate and sodium nitrate only

  20. Explain why the reaction of magnesium with steam is slower than the reaction of calcium with cold water.

    • Magnesium is less reactive because its ionisation energy is higher, so it loses electrons less readily
    • Calcium is a Group 1 metal, so it reacts more readily with steam and water than magnesium does in the reaction
    • Magnesium has more protons than calcium, so its nucleus shields the outer electrons more and makes them harder to lose
    • Magnesium is not a Group 2 element, so it does not react in the same way as calcium with water or steam

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