Group 2 — AS & A Level Chemistry (9701) questions by topic
Thermal decomposition and complex-ion chemistry both feature here: writing equations for calcium and barium carbonate decomposition, deducing gas volumes from anhydrous nitrate decomposition, and identifying complex-ion formulae such as [Cu(NH3)6]2+.
State, deduce, identify, calculate and explain lead 51 questions from 2023 to 2025 papers, worth 1 to 20 marks, so a slipped formula for a nitrate or copper complex can undermine an otherwise correct calculation. Instant marking after each formula and calculation answer catches a misformed Cu(NO3)2 or an impossible mole value before the same transcription error appears again in a later question.
What examiners look for
- A recurring criticism is writing the nitrate ion incorrectly as NO32, NO2 or NO rather than NO3-.
- Examiners note copper nitrate frequently written wrongly as CU(NO3)2 or cu(no3)2 instead of Cu(NO3)2.
- Reports flag not understanding that each formula unit of Cr2(SO4)3 contains two Cr3+ ions, which leads to an impossible answer.
- A common error described the ligand's denticity rather than the metal ion's coordination number.
- Strong scripts stated the standard definition of a polydentate ligand and, when working with d-orbital splitting, correctly noted that the two complexes have different delta E.
May–June 2025, Paper 11
Radium is an element below barium in Group 2 of the Periodic Table. Which equation shows what happens when solid radium nitrate, Ra(NO3)2, is heated strongly? A 2Ra(NO3)2(s) →…
Answer this question and get it marked →Each mineral listed behaves as a mixture of two carbonate compounds. They can be used as fire retardants because they decompose in the heat, producing CO2. This gas smothers the…
Answer this question and get it marked →May–June 2025, Paper 12
Which statement about strontium and its compounds is correct? A Strontium hydroxide is more soluble than barium hydroxide. B Strontium sulfate is more soluble than magnesium…
Answer this question and get it marked →1.0 g of each of four different compounds of Group 2 elements are thermally decomposed. The residue in each decomposition is the oxide of the Group 2 element. The volume of gas…
Answer this question and get it marked →May–June 2025, Paper 13
Which statement is correct? A Barium oxide reacts with water at room temperature to form barium hydroxide and hydrogen. B Calcium oxide does not react with water at room…
Answer this question and get it marked →W, X, Y and Z are Group 2 elements barium, calcium, magnesium and strontium but not in that order. W reacts faster with dilute hydrochloric acid than Y. The hydroxide of X is less…
Answer this question and get it marked →May–June 2025, Paper 14
Substance J reacts with water. A gas is given off and the pH of the solution increases. The solution is then reacted with sulfuric acid and a white precipitate forms. What could…
Answer this question and get it marked →The flow diagram shows two successive reactions starting from element Q. Element Q is either calcium or barium. Element Q forms a nitrate that is less thermally stable than…
Answer this question and get it marked →May–June 2025, Paper 41
Both calcium carbonate, CaCO3, and barium carbonate, BaCO3, decompose when heated to form the metal oxide and a gas. Write an equation for the thermal decomposition of CaCO3.
Answer this question and get it marked →May–June 2025, Paper 42
The thermal decomposition of Group 2 nitrates can be represented by the equation: M(NO3)2(s) → MO(s) + 2NO2(g) + ½O2(g) (i) Write the equation for the thermal decomposition of…
Answer this question and get it marked →May–June 2025, Paper 43
Both calcium carbonate, CaCO3, and barium carbonate, BaCO3, decompose when heated to form the metal oxide and a gas. Write an equation for the thermal decomposition of CaCO3.
Answer this question and get it marked →May–June 2025, Paper 44
Group 2 carbonates decompose on heating. (i) State and explain the trend in the thermal stability of Group 2 carbonates as the group is descended. (ii) Write the equation for the…
Answer this question and get it marked →May–June 2024, Paper 11
All solubility data in this question is given at the same temperature. The table gives some data for compounds of calcium and for compounds of X, an unidentified element in Group…
Answer this question and get it marked →What is the total volume of gas produced, measured at room conditions, when 0.010 mol of anhydrous magnesium nitrate is completely decomposed by heating? A 240 cm^3 B 480 cm^3 C…
Answer this question and get it marked →May–June 2024, Paper 12
A mixture of calcium carbonate, calcium nitrate, strontium carbonate and strontium nitrate is thermally decomposed. The decomposition reaction of each substance goes to…
Answer this question and get it marked →W is a solid that reacts with water to produce an alkaline solution. The addition of two drops of dilute H2SO4 to this alkaline solution produces a white precipitate. What could…
Answer this question and get it marked →May–June 2024, Paper 13
A sample consisting of 1.0 mol of anhydrous calcium nitrate is completely decomposed by strong heating. What is the total amount of gas produced in this reaction? A 1.0 mol B 2.0…
Answer this question and get it marked →Steam is passed over heated magnesium to give compound J and hydrogen. What is not a property of compound J? A It has an Mr of 40.3. B It is basic. C It is a white solid. D It is…
Answer this question and get it marked →May–June 2024, Paper 41
(i) Describe the trend in the solubility of the hydroxides of magnesium, calcium and strontium. Place them in order from most soluble to least soluble. Explain your answer. (ii)…
Answer this question and get it marked →May–June 2024, Paper 42
Describe the trend in the solubility of the sulfates of magnesium, calcium and strontium. Place them in order from most soluble to least soluble. Explain your answer.
Answer this question and get it marked →May–June 2024, Paper 43
(i) Describe the trend in the solubility of the hydroxides of magnesium, calcium and strontium. Place them in order from most soluble to least soluble. Explain your answer. (ii)…
Answer this question and get it marked →October–November 2024, Paper 11
V and W are two compounds. Each one contains a different Group 2 element. A sample of each solid is added to water, shaken, and the pH of the resulting solution is measured.…
Answer this question and get it marked →Compound L decomposes on heating. One of the products is gas M. M reacts with unburned hydrocarbons to form peroxyacetyl nitrate, PAN. What could be the formula of L? A CaNO₃ B…
Answer this question and get it marked →October–November 2024, Paper 12
X is a Group 2 element in either Period 3 or Period 5. X(OH)₂ is less soluble in water than Ca(OH)₂. When X(NO₃)₂ is heated, it decomposes. Which row is correct? identity of X…
Answer this question and get it marked →Which statement comparing magnesium and barium, or their compounds, is correct? A Magnesium reacts with dilute hydrochloric acid more rapidly than barium does. B One mole of…
Answer this question and get it marked →October–November 2024, Paper 13
V and W are two compounds. Each one contains a different Group 2 element. A sample of each solid is added to water, shaken, and the pH of the resulting solution is measured.…
Answer this question and get it marked →Compound L decomposes on heating. One of the products is gas M. M reacts with unburned hydrocarbons to form peroxyacetyl nitrate, PAN. What could be the formula of L? A CaNO₃ B…
Answer this question and get it marked →February–March 2023, Paper 12
A sample containing 0.010 mol of anhydrous calcium nitrate is heated strongly until it fully decomposes. All the gas produced is collected and its volume measured at room…
Answer this question and get it marked →In Group 2 of the Periodic Table, the properties of the elements and their compounds show regular change down the group. Which property shows a decrease from magnesium to barium?…
Answer this question and get it marked →Four properties of beryllium, Be, or a beryllium compound are listed. Which property is different from the property of magnesium or the equivalent magnesium compound? A Be reacts…
Answer this question and get it marked →May–June 2023, Paper 11
Which statement explains why calcium has a higher melting point than barium? A Calcium cations are smaller than barium cations and have a stronger attraction to the delocalised…
Answer this question and get it marked →For which compound is there the greatest percentage loss of mass on strong heating? A anhydrous calcium carbonate B anhydrous calcium nitrate C anhydrous magnesium carbonate D…
Answer this question and get it marked →A solution contains both Mg²⁺(aq) and Sr²⁺(aq) at the same concentration. The solution is divided into two equal portions. Aqueous sodium hydroxide is added dropwise to one…
Answer this question and get it marked →May–June 2023, Paper 12
The table compares calcium with barium and calcium carbonate with barium carbonate. Which row is correct? reactivity of the element with water thermal stability of the metal…
Answer this question and get it marked →Solutions P and Q each contain a different Group 2 ion at the same concentration. One contains Mg2+ and the other contains Ba2+. Tests are carried out on separate 5 cm3 samples of…
Answer this question and get it marked →May–June 2023, Paper 13
Equal volumes of saturated solutions of magnesium hydroxide, calcium hydroxide and strontium hydroxide are completely neutralised with dilute sulfuric acid. The water is gently…
Answer this question and get it marked →May–June 2023, Paper 41
Group 2 nitrates decompose when heated. Describe how the thermal stability of Group 2 nitrates changes with increasing proton number. Explain your answer.
Answer this question and get it marked →May–June 2023, Paper 42
Group 2 carbonates decompose when heated to form the metal oxide and carbon dioxide. Suggest a mechanism for the decomposition of the carbonate ion by adding two curly arrows in…
Answer this question and get it marked →May–June 2023, Paper 43
Group 2 nitrates decompose when heated. Describe how the thermal stability of Group 2 nitrates changes with increasing proton number. Explain your answer.
Answer this question and get it marked →October–November 2023, Paper 11
Which row correctly describes the separate reactions of calcium and strontium with water? A: substance reduced calcium or strontium, substance oxidised water, more vigorous…
Answer this question and get it marked →L and M are both compounds of Group 2 elements. L and M are both soluble in water. When solutions of L and M are mixed, a white precipitate is formed. What could be L and M? A:…
Answer this question and get it marked →A 5.00 g sample of an anhydrous Group 2 metal nitrate loses 3.29 g in mass when heated strongly. Which metal is present? A: magnesium. B: calcium. C: strontium. D: barium.
Answer this question and get it marked →October–November 2023, Paper 12
What happens when a piece of magnesium ribbon is placed in cold water? A: A vigorous effervescence occurs. B: Bubbles of gas form slowly on the magnesium. C: The magnesium floats…
Answer this question and get it marked →The table gives some data for compounds of two elements from Group 2: for calcium the decomposition temperature of the carbonate is 840 degrees C, solubility of sulfate 4.66 x…
Answer this question and get it marked →Q is a mixture of two compounds of Group 2 elements. Q undergoes thermal decomposition to produce a white solid and only two gaseous products; one of the gaseous products relights…
Answer this question and get it marked →October–November 2023, Paper 13
Which row correctly describes the separate reactions of calcium and strontium with water? substance reduced substance oxidised more vigorous reaction --- --- --- --- A calcium or…
Answer this question and get it marked →L and M are both compounds of Group 2 elements. L and M are both soluble in water. When solutions of L and M are mixed, a white precipitate is formed. What could be L and M? A…
Answer this question and get it marked →A 5.00 g sample of an anhydrous Group 2 metal nitrate loses 3.29 g in mass when heated strongly. Which metal is present? A magnesium B calcium C strontium D barium
Answer this question and get it marked →October–November 2023, Paper 21
Barium hydroxide, Ba(OH)2, is a strong base used in inorganic and organic reactions. Fig. 2.1 shows a reaction scheme involving Ba(OH)2: BaO(s) reacts with H2O(l) in reaction 1 to…
Answer this question and get it marked →October–November 2023, Paper 23
Barium hydroxide, Ba(OH)2, is a strong base used in inorganic and organic reactions. Fig. 2.1 shows a reaction scheme involving Ba(OH)2: BaO(s) reacts with H2O(l) in reaction 1 to…
Answer this question and get it marked →October–November 2023, Paper 42
Some of the ionic compounds of Group 2 elements undergo thermal decomposition. Thermal decomposition of solid anhydrous magnesium ethanedioate, MgC₂O₄, occurs above 650 °C; the…
Answer this question and get it marked →Other AS & A Level Chemistry topics
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