Q21 · 2023 · Paper 1Simple familiar4 marks
QUESTION 21 (4 marks)
Describe how the atomic model proposed by Bohr addresses the limitation of Rutherford’s model.
WORKED SOLUTION
4 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
4r 1: Short response
Sample response The
The Rutherford model provided evidence for the presence of • de
electrons around the nucleus of an atom, while the Bohr atomic f1
model described how electrons orbit the nucleus. • de
However, Rutherford’s model was limited, because it couldn't • de
account for the stability of atoms, as electrons orbiting the m
nucleus would gradually lose energy and spiral into the nucleus. |, de
The Bohr model addressed this by explaining the quantised le
nature of these orbits and how electrons within the same orbit
possess the same discrete quantity of energy.
e describes Rutherford’s atomic model
[1 mark]
e describes Bohr's atomic model [1 mark]
e describes a limitation of Rutherford’s atomic
model [1 mark]
e describes significance of quantised energy
levels [1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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