9. The Periodic Table: chemical periodicity
A section of Chemistry, 9701
Listing 10 of 288 questions
The mass spectrum of silicon is shown. 1.0 0.5 0.047 0.031 0.922 m / e relative intensity Calculate the Ar of silicon. Give your answer to two decimal places. Ar = Silicon forms a low boiling point chloride which reacts with water. Write an equation to show the reaction of the chloride with water. Draw a three-dimensional diagram showing the shape of the chloride. Give the Cl – Si – Cl bond angle. Silicon reacts with oxygen to form a high melting point oxide. ● Suggest the formula of the oxide. ● Suggest, in terms of structure, why the oxide has a high melting point whereas the chloride has a low boiling point. Element A is in the same period as silicon. Element A reacts with dilute nitric acid to form a nitrate. This nitrate decomposes on heating to form an oxide. Write an equation for the decomposition of the nitrate. The oxide of element A has a high melting point. Suggest the structure and bonding present in the oxide of A.
9701_m17_qp_42
THEORY
2017
Paper 4, Variant 2
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Copper, proton number 29, and argon, proton number 18, are elements which have different physical and chemical properties. In the solid state, each element has the same face-centred cubic crystal structure which is shown below. The particles present in such a crystal may be atoms, molecules, anions or cations. In the diagram above, the particles present are represented by . Which types of particle are present in the copper and argon crystals? In each case, give their formula. element particle formula copper argon At room temperature, copper is a solid while argon is a gas. Explain these observations in terms of the forces present in each solid structure. Although copper is a relatively unreactive element, when it is heated to a high temperature in an excess of chlorine, copper(chloride is formed. When a mixture of argon and chlorine is heated to a high temperature, no reaction occurs. How does chlorine behave in its reaction with copper? Suggest a reason for the lack of a reaction between argon and chlorine. The melting points of the noble gases neon to xenon are given below. Ne Ar Kr Xe melting point /K Explain why there is an increase in melting point from neon to xenon.
9701_s10_qp_22
THEORY
2010
Paper 2, Variant 2
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This question refers to the elements in the section of the Periodic Table shown below. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca transition elements Ga Ge As Se Br Kr From this list of elements, identify in each case one element that has the property described. Give the symbol of the element. An element that fl oats on cold water and reacts readily with it. An element that forms an oxide that is a reducing agent. The element that has the smallest fi rst ionisation energy. The element which has a giant molecular structure and forms an oxide which has a simple molecular structure. The element in Period 3 (Na to Ar) that has the smallest anion. The element in Period 3 (Na to Ar) which forms a chloride with a low melting point and an oxide with a very high melting point. Use the elements in Period 3 (Na to Ar) in the section of the Periodic Table opposite to identify the oxidereferred to below. In each case, give the formula of the oxide. An oxide which when placed in water for a long time has no reaction with it. An oxide which dissolves readily in water to give a strongly alkaline solution. Two acidic oxides formed by the same element. and An oxide which is amphoteric. Fluorine reacts with other elements in Group VII to form a number of different compounds. Two such compounds and their boiling points are given in the table. compound Cl F3 BrF3 boiling point / °C The two molecules have similar electronic confi gurations. Showing outer electrons only, draw a 'dot-and-cross' diagram of the bonding in Cl F3. The two molecules have the same shape. Suggest why the boiling points are signifi cantly different.
9701_s13_qp_21
THEORY
2013
Paper 2, Variant 1
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This question refers to the elements in the section of the Periodic Table shown below. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca transition elements Ga Ge As Se Br Kr From this list of elements, identify in each case one element that has the property described. Give the symbol of the element. An element that when placed in cold water sinks and reacts readily. An element whose molecules contain π bonding. An element that forms a gaseous toxic oxide. The element which has a giant molecular structure and forms an oxide which also has a giant molecular structure. An element that forms a covalent chloride which dissolves in water to give a conducting solution. The element in Period 3 (Na to Ar) with the greatest electrical conductivity. Some of the elements in Period 3 (Na to Ar) burn with a coloured fl ame when heated in oxygen or chlorine. Give the symbol of one such element, the formula of the oxide formed, and state the fl ame colour that would be seen. symbol of element formula of oxide fl ame colour For the element you have used in , give the formula of the chloride formed, and state the pH of the solution produced when this chloride is shaken with water. formula of chloride pH of solution Chlorine reacts with both bromine and iodine to form BrCl and ICl respectively. The melting points of chlorine and the two chlorides are shown in the table. substance Cl 2 BrCl ICl m.p. / °C –101 –66 Showing outer electrons only draw a 'dot-and-cross' diagram of the bonding in ICl . Suggest why the melting points increase from Cl 2 to ICl . Suggest which of these three molecules has the largest permanent dipole. Explain your answer.
9701_s13_qp_22
THEORY
2013
Paper 2, Variant 2
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This question refers to the elements in the section of the Periodic Table shown below. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca transition elements Ga Ge As Se Br Kr From this list of elements, identify in each case one element that has the property described. Give the symbol of the element. An element that has molecules which consist of single atoms. An element that has a molecule which contains exactly four atoms. The element that is a liquid at room temperature and pressure. The element in Period 3 (Na to Ar) that has the largest atomic radius. The element in Period 3 (Na to Ar) that has the highest melting point. The element in Period 3 (Na to Ar) that forms the largest anion. An element that reacts with water to give a solution that can behave as an oxidising agent. The formulae and melting points of some of the oxides of the elements in Period 3, Na to Cl, are given in the table. formula of oxide Na2O MgO Al 2O3 SiO2 P4O6 SO2 Cl 2O7 m.p. / °C –73 –92 Give the formulae of two of these oxides that have simple molecular structures. and Give the formula of one of these oxides that will give no reaction with water when placed in it for a long time. Give the formula of the product formed when MgO is reacted with SO2. The melting points of the elements Si to Cl are given in the table. element Si P S Cl m.p. / °C –102 Explain why the melting point of Si is very much greater than those of the other three elements. Suggest why the melting points of the other three elements are in the order S > P > Cl.
9701_s13_qp_23
THEORY
2013
Paper 2, Variant 3
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