FRQ — Classification of Elements and Periodicity in Properties

Case study·Standard multi-step (3/5)·No calculator

Difficulty guide

The label describes the problem, not your ability.

1/5 - Foundational

Warm-up setup; checks one basic idea.

2/5 - Routine exam skill

Normal syllabus skill; usually one main rule or interpretation.

3/5 - Standard multi-step

Exam-style problem with multiple steps or a common trap.

4/5 - Hard exam skill

High-end exam problem; combines methods carefully.

5/5 - Challenge

Stretch problem beyond normal exam pressure.

Question

A student compares three period-3 oxides:

\mathrm{Na_2O}

\mathrm{Al_2O_3}

and

\mathrm{SO_3}

. The student says all oxides in a period must have the same acid-base character because they are in the same row.

Total: 5 marks

(a) Classify $\mathrm{Na_2O}$ as basic, acidic or amphoteric. (1 mark)

(b) Classify $\mathrm{Al_2O_3}$ . (1 mark)

Your response (optional — you can also work on paper)

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