February/March 2026 Paper 42

2026 · 6 questions · 51 parts · 80 marks

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Context for question 2

Aluminium and indium are elements in Group III of the Periodic Table.

2(a)

Aluminium is extracted from its purified main ore. The purified ore is mainly aluminium oxide. During this extraction process aluminium oxide is broken down into its elements.

2(a)(i)Metal ExtractionEasy1 mark

Name the main ore of aluminium.

2(a)(ii)Metal ExtractionEasy1 mark

Name the process in which aluminium oxide is broken down into its elements.

2(a)(iii)Metal ExtractionEasy1 mark

Name the substance which is added to aluminium oxide to reduce the operating temperature of this process.

2(b)

Aluminium oxide reacts with both acids and bases to form salts.

2(b)(i)Acid Base Properties ReactionsEasy1 mark

State the type of oxide that reacts with both acids and bases.

2(b)(ii)Acid Base Properties ReactionsEasy2 marks

State the name and give the formula of the salt formed when aluminium oxide reacts with dilute hydrochloric acid.

Name of the salt

Formula of the salt

2(c)

The salt formed when aluminium oxide reacts with aqueous sodium hydroxide is sodium aluminate, NaAlO

_{2}

2(c)(i)Formulae Chemical EquationsEasy2 marks

Complete the equation for the reaction of aluminium oxide with aqueous sodium hydroxide by inserting the missing formula and balancing the equation.

A l_{2} O_{3} + \dots\dots NaOH \to \dots\dots NaAl O_{2} + \dots\dots\dots\dots

Missing formula and coefficients

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2(c)(ii)Formulae Chemical EquationsEasy1 mark

Write the formula of the anion in NaAlO

_{2}

2(d)

Indium has an atomic number of 49.

2(d)(i)Electron Configuration OrbitalsEasy1 mark

State the number of occupied electron shells in an atom of indium.

2(d)(ii)Atomic Structure IsotopesEasy2 marks

A sample of indium contains two isotopes,

^{113}

In and

^{115}

In.

Complete Table 2.1 to show the number of protons and the number of neutrons in one atom of each isotope of indium.

isotope	number of protons	number of neutrons
$^{113}$ In	Table answer r1_number of protons	Table answer r1_number of neutrons
$^{115}$ In	Table answer r2_number of protons	Table answer r2_number of neutrons

2(d)(iii)Atomic Structure IsotopesEasy2 marks

Table 2.2 shows the relative abundances of the two isotopes in the sample of indium.

Table 2.2

isotope	$^{113}$ In	$^{115}$ In
relative abundance	1	19

Calculate the relative atomic mass of this sample of indium to one decimal place.

Relative atomic mass

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