Chemistry SL
Structure 3: classification of matter — Structure 3
- 1.
State how elements are arranged in the modern periodic table, and how this arrangement relates to electron configuration.
[3 marks] · no calculator - 2.
Marking analysis: A learner attempts the following task: “State how elements are arranged in the modern periodic table, and how this arrangement relates to electron configuration.” Their response addresses only this point: “States that elements are arranged in order of increasing atomic number.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 3.
Explain why the first ionization energies generally increase across period 3 (from sodium to argon), despite some small irregularities.
[4 marks] · no calculator - 4.
Marking analysis: A learner attempts the following task: “Explain why the first ionization energies generally increase across period 3 (from sodium to argon), despite some small irregularities.” Their response addresses only this point: “States that nuclear charge increases across the period as protons are added.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] · no calculator - 5.
Explain why atomic radius decreases across a period but increases down a group.
[3 marks] · no calculator - 6.
Marking analysis: A learner attempts the following task: “Explain why atomic radius decreases across a period but increases down a group.” Their response addresses only this point: “States that across a period, nuclear charge increases while shielding stays roughly constant, so the increased effective nuclear attraction pulls the outer electrons closer, decreasing atomic radius.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 7.
Describe the general trend in electronegativity across a period and down a group, and state which element is the most electronegative.
[3 marks] · no calculator - 8.
Marking analysis: A learner attempts the following task: “Describe the general trend in electronegativity across a period and down a group, and state which element is the most electronegative.” Their response addresses only this point: “States that electronegativity generally increases across a period.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 9.
Ethanol and methoxymethane have the same molecular formula, C₂H₆O. Explain why ethanol has the higher boiling point.
[4 marks] · no calculator - 10.
Marking analysis: A learner attempts the following task: “Ethanol and methoxymethane have the same molecular formula, C₂H₆O. Explain why ethanol has the higher boiling point.” Their response addresses only this point: “States that ethanol has an −OH functional group, allowing its molecules to form hydrogen bonds with each other.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] · no calculator - 11.
Propane, C₃H₈, is a member of the alkane homologous series. State the general formula of the alkanes and use it to write the molecular formula of the alkane with 6 carbon atoms.
[3 marks] · no calculator - 12.
Marking analysis: A learner attempts the following task: “Propane, C₃H₈, is a member of the alkane homologous series. State the general formula of the alkanes and use it to write the molecular formula of the alkane with 6 carbon atoms.” Their response addresses only this point: “States the general formula CₙH₂ₙ₊₂.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 13.
Identify the functional group present in a carboxylic acid, and state the general formula of the homologous series.
[2 marks] · no calculator - 14.
Marking analysis: A learner attempts the following task: “Identify the functional group present in a carboxylic acid, and state the general formula of the homologous series.” Their response addresses only this point: “Identifies the carboxyl functional group, −COOH.” Evaluate the response against the complete 2-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[2 marks] · no calculator - 15.
Explain how infrared (IR) spectroscopy can be used to identify the presence of a carbonyl group (C=O) in an organic molecule.
[3 marks] · no calculator - 16.
Marking analysis: A learner attempts the following task: “Explain how infrared (IR) spectroscopy can be used to identify the presence of a carbonyl group (C=O) in an organic molecule.” Their response addresses only this point: “States that different bonds absorb infrared radiation at characteristic frequencies (wavenumbers), causing them to vibrate.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 17.
A mass spectrum of an organic compound shows a molecular ion peak at m/z = 46. Suggest the molecular formula of a compound consistent with this molecular mass, given it contains only carbon, hydrogen and oxygen.
[3 marks] - 18.
Marking analysis: A learner attempts the following task: “A mass spectrum of an organic compound shows a molecular ion peak at m/z = 46. Suggest the molecular formula of a compound consistent with this molecular mass, given it contains only carbon, hydrogen and oxygen.” Their response addresses only this point: “States that the molecular ion peak (M+) gives the relative molecular mass of the compound directly.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] - 19.
Distinguish between a saturated and an unsaturated hydrocarbon, and describe a simple chemical test to distinguish between them.
[3 marks] · no calculator - 20.
Marking analysis: A learner attempts the following task: “Distinguish between a saturated and an unsaturated hydrocarbon, and describe a simple chemical test to distinguish between them.” Their response addresses only this point: “States that a saturated hydrocarbon contains only single carbon-carbon bonds, e.g. alkanes.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 21.
State the general position of metals, non-metals and metalloids in the periodic table, and state one physical property that generally distinguishes metals from non-metals.
[3 marks] · no calculator - 22.
Marking analysis: A learner attempts the following task: “State the general position of metals, non-metals and metalloids in the periodic table, and state one physical property that generally distinguishes metals from non-metals.” Their response addresses only this point: “States that metals are found on the left and towards the bottom of the periodic table, while non-metals are found on the right and towards the top.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 23.
Distinguish between chain isomerism and position isomerism, giving one example of each.
[2 marks] · no calculator - 24.
Marking analysis: A learner attempts the following task: “Distinguish between chain isomerism and position isomerism, giving one example of each.” Their response addresses only this point: “States that chain isomers have the same molecular formula but a different arrangement of the carbon skeleton (branching), e.g. butane and methylpropane.” Evaluate the response against the complete 2-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[2 marks] · no calculator - 25.
But-1-ene and but-2-ene are structural isomers with molecular formula C₄H₈. Explain what the numbers '1' and '2' indicate, and state the type of structural isomerism this represents.
[3 marks] · no calculator - 26.
Marking analysis: A learner attempts the following task: “But-1-ene and but-2-ene are structural isomers with molecular formula C₄H₈. Explain what the numbers '1' and '2' indicate, and state the type of structural isomerism this represents.” Their response addresses only this point: “States that the number indicates the position of the carbon-carbon double bond within the carbon chain.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 27.
Outline how ¹H NMR (proton nuclear magnetic resonance) spectroscopy can be used to determine the number of different hydrogen (proton) environments in an organic molecule.
[3 marks] · no calculator - 28.
Marking analysis: A learner attempts the following task: “Outline how ¹H NMR (proton nuclear magnetic resonance) spectroscopy can be used to determine the number of different hydrogen (proton) environments in an organic molecule.” Their response addresses only this point: “States that hydrogen atoms in different chemical environments, bonded differently within the molecule, absorb energy at slightly different frequencies in a strong magnetic field.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 29.
Describe and explain the general trend in melting point across period 3, from sodium to argon, in terms of the type of structure and bonding present.
[4 marks] · no calculator - 30.
Marking analysis: A learner attempts the following task: “Describe and explain the general trend in melting point across period 3, from sodium to argon, in terms of the type of structure and bonding present.” Their response addresses only this point: “States that Na, Mg and Al are metals with metallic bonding, with melting point increasing from Na to Al as the number of delocalised electrons per atom and ionic charge increase, strengthening the metallic bonding.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] · no calculator