Chlorine atoms have electron arrangement 2,8,7. Iodine atoms have more occupied electron shells but also seven outer electrons.
.1
Explain why chlorine is more reactive than iodine.
[3 marks]
.2
Compare this trend with the reactivity trend down group 1.
[2 marks]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
An oxygen molecule contains two oxygen atoms. Each atom has six outer electrons.
.1
Explain the bonding needed for both atoms to achieve full outer shells.
[3 marks]
.2
Explain why a line drawing O=O does not show every electron.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A coastal authority receives projections of sea-level rise between 0.25 m and 0.70 m by a stated date. The range reflects different future emissions and model uncertainty.
Explain why the range does not mean that no action is justified, and identify two scientific causes of rising sea level.
[4 marks]
5 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A container holds 1.5 dm³ of a solution with concentration 8.0 g/dm³. The solvent evaporates and 1.0 dm³ remains. No solute is lost.
.1
Calculate the final concentration.
[3 marks]
.2
Explain why the concentration changes even though no solute is added.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A town collects 12 tonnes of glass. Sorting removes 8% as contamination. All remaining glass can replace virgin glass material in this simplified model.
.1
Calculate the mass available to replace virgin material.
[2 marks]
.2
Explain why reducing packaging use can give benefits beyond recycling the same mass.
