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CAIE IGCSE Chemistry Roman Numerals and Oxidation Numbers

Practise interpreting Roman numerals as oxidation numbers, calculating the metal value from a formula and writing names such as iron(III) oxide.

Syllabus
2026–2028
Course
Chemistry 0620

Exam points

  • state that a Roman numeral gives the named element's oxidation number, not an atom count
  • use ion charges and formula subscripts to determine the required oxidation number
  • write a full compound name with the correct Roman numeral for a variable-charge metal

6.4.1—Roman numeral to indicate the question 1

[Maximum number: 1]

Sulfur is a Group VI element.

Na2SO3\mathrm{Na}_{2} \mathrm{SO}_{3} is oxidised by acidified aqueous potassium manganate(VII).

State what VII refers to in the name potassium manganate(VII).

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