Figure 3 represents different models of the atom.
Figure 3
Which diagram shows the plum pudding model of the atom?
Tick one box
[1 mark]
ANSWER
B
Which diagram shows the model of the atom developed from the alpha particle scattering experiment? Tick one box.
[1 mark]
A |
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| B |
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| C |
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| D |
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| E |
ANSWER
C
Which diagram shows the model of the atom resulting from Bohr’s work?
Tick one box.
[1 mark]
ANSWER
A
Define the mass number of an atom.
[1 mark]
ANSWER
Mass number is the sum of protons and neutrons
Element X has two isotopes. Their mass numbers are 69 and 71.
The percentage abundance of each isotope is:
• 60% of 69X
• 40% of 71X
Estimate the relative atomic mass of element X.
[1 mark]
ANSWER
Between 69.5 and 70.0
Chadwick’s experimental work on the atom led to a better understanding of isotopes. Explain how his work led to this understanding.
[3 marks]
ANSWER
In 1932, James Chadwick discovered a new particle inside the nucleus that had the same mass as a proton but had no electric charge. This particle was given the name neutron. This was necessary because isotopes have the same number of protons but with different numbers of neutrons.
