9. The Periodic Table: chemical periodicity
A section of Chemistry, 9701
Listing 10 of 288 questions
The table gives some data for elements in the third period and some of their compounds. element Na Mg Al Si P S type of bonding metallic covalent covalent formula of oxide P4O10 SO2 formula of chloride NaCl MgCl 2 SCl 2 Complete the table to show the bonding in the elements, and the formulae of their oxides and chlorides. SCl 2 is formed in the following reaction. S2Cl 2+ Cl 22SCl 2ΔH = – 40.6 kJ mol–1 Complete the ‘dot-and-cross’ diagram to show the bonding in a molecule of SCl 2. Show outer electrons only.  Complete and fully label the reaction pathway diagram for the reaction between S2Cl 2 and Cl 2. Include labels for activation energy, Ea, and enthalpy change of the forward reaction, ΔH. energy progress of reaction S2Cl 2+ Cl 2 On the axes, sketch the trend in melting point of the elements Na to S. melting point of element Na Mg Al Si P S  Give three statements to explain your sketch.  Write an equation for the reaction of P4O10 with water. SO2 can be released into the atmosphere when fossil fuels containing sulfur are burnt. State and explain one environmental consequence of the release of SO2 into the atmosphere. The elements in the third period show a general increase in their first ionisation energies from left to right. Identify two pairs of successive elements in the third period that do not agree with this statement. For each pair, explain why the change in ionisation energy does not agree with this statement. Use of the Data Booklet may help you to answer this question. pair 1 explanation pair 2 explanation  
9701_w18_qp_22
THEORY
2018
Paper 2, Variant 2
View
Oxygen is the most abundant element in the Earth’s crust. It reacts with other elements to form stable compounds, ions and molecules. Complete the table to give the formulae and acid/base behaviour of some of the oxides of the Period3 elements. element sodium aluminium silicon phosphorus sulfur formula of oxide Na2O SO3 acid/base behaviour amphoteric  Group2 elements form stable hydroxides, with general formula M(OH)2, where M is the Group2 element. Beryllium hydroxide, Be(OH)2, is an amphoteric compound that shows similar chemical reactions to aluminium oxide. State the meaning of the term amphoteric. Write an ionic equation for the reaction of magnesium hydroxide, Mg(OH)2, with hydrochloricacid. Two methods of preparing strontium hydroxide are shown. strontium strontium hydroxide strontium oxide H2O reaction 1 H2O reaction 2 State one difference between the observations you would make for reaction 1 and reaction2. State how the solubility of the Group2 hydroxides changes down the group. Sodium peroxide, Na2O2, reacts with CO2. Na2O2+ CO2Na2CO3+ 2O2The partial pressure of CO2in a 0.500 dm3 sample of air is 5.37 kPa at 20 °C. Calculate the amount, in moles, of CO2present in the sample of air at 20 °C.  amount of CO2= mol Calculate the mass of Na2O2that would react fully with the amount of CO2calculated in .  mass of Na2O2= g The peroxide ion, O2 2–, has a single covalent bond between the two oxygen atoms. Each oxygen atom carries a negative charge. Draw a ‘dot-and-cross’ diagram for the peroxide ion. Show outer electrons only.  
9701_w19_qp_22
THEORY
2019
Paper 2, Variant 2
View
Phosphorus, sulfur and chlorine can all react with oxygen to form oxides. Phosphorus reacts with an excess of oxygen to form phosphorus(oxide. Write an equation to show the reaction of phosphorus with excess oxygen. Describe the reaction of phosphorus(oxide with water. State the structure and bonding of solid phosphorus(oxide. The two most common oxides of sulfur are SO2 and SO3. When SO2 dissolves in water, a small proportion of it reacts with water to form a weak Brønsted‑Lowry acid. Explain the meaning of the term weak Brønsted-Lowry acid. Write the equation for the reaction of SO2 with water. SO2 reacts with NO2 in the atmosphere to form SO3 and NO. NO is then oxidised in air to form NO2. SO2 + NO2 → SO3 + NO 2NO + O2 → 2NO2 State the role of NO2 in this two-stage process. Emissions of SO2 from coal-fired power stations can be reduced by mixing the coal with powdered limestone. Limestone is heated to form CaO in reaction1. This then reacts with SO2 and O2 to form CaSO4 in reaction2. reaction 1: CaCO3→ CaO+ CO2reaction 2: CaO+ SO2+ 1 2O2→ CaSO4State the type of reaction occurring in reaction1. Use the data to calculate the enthalpy change of reaction2. compound ∆Hf / kJ mol–1 CaO–635 SO2–297 CaSO4–1434  enthalpy change of reaction2 = kJ mol–1 Chlorine forms several oxides, including Cl 2O, Cl O2 and Cl 2O6. Draw a ‘dot-and-cross’ diagram of Cl 2O. Show outer-shell electrons only.  Cl O2 can be prepared by reacting NaCl O2 with Cl 2. Write the oxidation state of chlorine in each species in the boxes provided. 2NaCl O2 + Cl 2 → 2Cl O2 + 2NaCl oxidation state of chlorine: +3  Cl 2O6is produced by the reaction of Cl O2with O3. 2Cl O2+ 2O3Cl 2O6+ 2O2∆H = –216 kJ mol–1 The reaction takes place at 500 K and 100 kPa. State and explain the effect on the yield of Cl 2O6when the experiment is carried out: ● at 1000 K and 100 kPa ● at 500 K and 500 kPa.  ElementE is a Period5 element. E reacts with oxygen to form an insoluble white oxide that has a melting point of 1910 °C. The oxide of E conducts electricity only when liquid. E also reacts readily with Cl 2to form a white solid that reacts exothermically with water. The resulting solution reacts with aqueous silvernitrate to form a white precipitate that dissolves in dilute ammonia. Suggest the type of bonding shown by the oxide of E. Explain your answer. Suggest the type of bonding shown by the chloride of E. Explain your answer. 
9701_w20_qp_21
THEORY
2020
Paper 2, Variant 1
View
The Period3 elements, Na to S, all react with oxygen to form oxides. State the trend in acid/base behaviour of the oxides of the Period3 elements, from Na to S. State and explain the trend, from Na to S, in the maximum oxidation number of the Period3 elements in their oxides. Sodiumoxide and phosphorus(oxide both react with water. Name the product of each reaction. reaction product sodium oxide with water phosphorus(oxide with water  Explain why phosphorus(oxide has a low melting point of approximately 300 °C but magnesiumoxide has a high melting point of approximately 2850 °C. Aluminiumoxide, Al 2O3, reacts separately with both acids and alkalis. Write an equation for the reaction of aluminiumoxide with excess aqueous hydrochloricacid. Write an equation for the reaction of aluminiumoxide with excess aqueous sodiumhydroxide. Describe the lattice structure of silicon(oxide. Your answer should include reference to the arrangement of the silicon and oxygen atoms and the bonds between them. Sodiumoxide and silicon(oxide react to form sodiumsilicate(, Na2SiO3. Sodiumoxide is obtained from the thermal decomposition of sodiumcarbonate. Write equations for the following reactions: sodiumoxide with silicon(oxide the thermal decomposition of sodiumcarbonate, forming sodiumoxide and carbondioxide. 
9701_w20_qp_22
THEORY
2020
Paper 2, Variant 2
View
Phosphorus, sulfur and chlorine can all react with oxygen to form oxides. Phosphorus reacts with an excess of oxygen to form phosphorus(oxide. Write an equation to show the reaction of phosphorus with excess oxygen. Describe the reaction of phosphorus(oxide with water. State the structure and bonding of solid phosphorus(oxide. The two most common oxides of sulfur are SO2 and SO3. When SO2 dissolves in water, a small proportion of it reacts with water to form a weak Brønsted‑Lowry acid. Explain the meaning of the term weak Brønsted-Lowry acid. Write the equation for the reaction of SO2 with water. SO2 reacts with NO2 in the atmosphere to form SO3 and NO. NO is then oxidised in air to form NO2. SO2 + NO2 → SO3 + NO 2NO + O2 → 2NO2 State the role of NO2 in this two-stage process. Emissions of SO2 from coal-fired power stations can be reduced by mixing the coal with powdered limestone. Limestone is heated to form CaO in reaction1. This then reacts with SO2 and O2 to form CaSO4 in reaction2. reaction 1: CaCO3→ CaO+ CO2reaction 2: CaO+ SO2+ 1 2O2→ CaSO4State the type of reaction occurring in reaction1. Use the data to calculate the enthalpy change of reaction2. compound ∆Hf / kJ mol–1 CaO–635 SO2–297 CaSO4–1434  enthalpy change of reaction2 = kJ mol–1 Chlorine forms several oxides, including Cl 2O, Cl O2 and Cl 2O6. Draw a ‘dot-and-cross’ diagram of Cl 2O. Show outer-shell electrons only.  Cl O2 can be prepared by reacting NaCl O2 with Cl 2. Write the oxidation state of chlorine in each species in the boxes provided. 2NaCl O2 + Cl 2 → 2Cl O2 + 2NaCl oxidation state of chlorine: +3  Cl 2O6is produced by the reaction of Cl O2with O3. 2Cl O2+ 2O3Cl 2O6+ 2O2∆H = –216 kJ mol–1 The reaction takes place at 500 K and 100 kPa. State and explain the effect on the yield of Cl 2O6when the experiment is carried out: ● at 1000 K and 100 kPa ● at 500 K and 500 kPa.  ElementE is a Period5 element. E reacts with oxygen to form an insoluble white oxide that has a melting point of 1910 °C. The oxide of E conducts electricity only when liquid. E also reacts readily with Cl 2to form a white solid that reacts exothermically with water. The resulting solution reacts with aqueous silvernitrate to form a white precipitate that dissolves in dilute ammonia. Suggest the type of bonding shown by the oxide of E. Explain your answer. Suggest the type of bonding shown by the chloride of E. Explain your answer. 
9701_w20_qp_23
THEORY
2020
Paper 2, Variant 3
View
Questions Discovered
288