Chemistry · Oct / Nov 2025 · Paper 41 · Question 1
0620
As printed in the paper
The question as text
Protons, neutrons and electrons are particles found in atoms.
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1(a)[2]
particle
relative
relative
mass
charge
proton
1
neutron
1
0 / nil
electron
– 1
✓(1)
✓(1)
1(b)(i)[2]
M1 atoms of the same element that have the same number of protons
M2 but different numbers of neutrons
1(b)(ii)[1]
they have the same number of electrons and therefore the same electronic configuration
1(c)[5]
M1 22
M2 16 and 18
M3 50 and 22 and to the left of the symbol
M4 Ti
M5 2+
1(d)[1]
nucleon number
1(e)[2]
M1 mol Ar = 2.0 ‣ 40 = 0.05 (mol)
M2 number of atoms = 0.05 × 6.02 × 1023 = 3.01 × 1022
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