Actual 2025/2026 AQA A-LEVEL CHEMISTRY 7405/1 Paper 1 Merged Question Paper + Mark Scheme + Insert

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0 1 This question is about atomic structure.
0 1 . 1 In 1897 JJ Thomson discovered the electron. He suggested that atoms were
positively charged spheres with electrons embedded within them.
Figure 1 represents an atom using Thomson’s model.
Figure 1
Suggest the identity of this atom.
Give two differences between the modern model of an atom and the Thomson model
of an atom.
[3 marks]
Identity
Difference 1
Difference 2
3
*03*
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box 0 1 . 2 Tellurium has a relative atomic mass of 127.6
Iodine has a relative atomic mass of 126.9
Define relative atomic mass.
Suggest one property of tellurium that justifies its position before iodine in the
modern Periodic Table.
[3 marks]
Definition
Justification
0 1 . 3 A sample of tellurium is analysed in a time of flight (TOF) mass spectrometer using
electron impact ionisation.
Give an equation, including state symbols, for this ionisation.