Starter quiz
- Which of these are examples of natural sources of background radiation?
- cosmic rays ✓
- nuclear fallout
- nuclear waste
- medical treatments
- granite rock ✓
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- Which of these devices is used to detect nuclear radiation?
- an ammeter
- a Van de Graaff generator
- a Geiger counter ✓
- a voltmeter
- a joulemeter
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The figure shows a model of the atom developed by JJ Thompson. It is the ______ model of the atom.- 'plum pudding' ✓
- Which particles did Rutherford use in his experiment which led to the development of the nuclear model of the atom?
- gamma particles
- beta particles
- alpha particles ✓
- neutrons
- protons
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- Which of these are conclusions from Rutherford’s scattering experiment?
- atoms are mostly empty space ✓
- the nucleus contains protons
- the nucleus contains neutrons
- the nucleus has most of the mass of the atoms ✓
- the nucleus is positively charged ✓
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- Which of these refinements of the nuclear model is Niels Bohr responsible for?
- the discovery of protons in the nucleus
- the discovery of electrons around the nucleus
- the discovery of neutrons in the nucleus
- the energy level (shell) structure of electrons in atoms ✓
- background radiation
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Exit quiz
- Match each key word or phrase to the correct definition.
- nucleus⇔the central part of an atom that contains protons and neutrons ✓
- nucleon⇔a proton or neutron in a nucleus ✓
- atomic (proton) number⇔the number of protons within a particular nucleus ✓
- mass (nucleon) number⇔the total number of protons + neutrons within a particular nucleus ✓
- isotopes⇔atoms of the same element with differing numbers of neutrons ✓
- Which of the following particles has the smallest mass?
- a neutron
- a helium atom
- a proton
- an electron ✓
- a gold atom
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- Nuclei can be represented by nuclear notation (X). For example, Ne. Which of these statements about this notation are correct?
- Z shows the number of protons in the nucleus ✓
- Z shows the number of neutrons in the nucleus
- A shows the number of protons in the nucleus
- A shows the number of neutrons in the nucleus
- A shows the total number of protons and neutrons in the nucleus ✓
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- A sulfur atom is represented by the symbol S. Which of these statements are correct?
- the atom contains 34 neutrons
- the atom contains 16 protons ✓
- the atom contains 18 neutrons ✓
- the atom contains 16 electrons ✓
- the atom contains 34 protons
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- Which of these statements about neutrons are correct?
- Neutrons are always stable particles
- Neutrons are more stable when close to a proton inside a nucleus. ✓
- Neutrons are less stable when close to a proton inside a nucleus.
- Neutrons are much more massive than protons.
- Neutrons and protons have similar masses. ✓
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- There are 13 known isotopes of lithium. The most common is lithium-7, which can be represented as Li. Which of these statements about the nuclei of other isotopes of lithium are correct?
- They are all the same element. ✓
- They all have 3 protons in their nucleus. ✓
- They all have 4 neutrons in their nucleus.
- They all have the same mass.
- They all have the same number of electrons. ✓
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Protons have a positive electric charge of +1 and a mass number of 1.
- Neutrons have no electric charge and have a mass number of 1.
- The atomic number of an element equals the number of protons in the nucleus of each atom of that element.
- The atomic number of an element equals the number of electrons in each atom of that element.
- Atoms of an element that have different numbers of neutrons in their nuclei are isotopes of the element.
Common misconception
Many pupils are uncertain about the forces attracting or repelling particles inside an atom.
Extend explanations to include electrostatic forces between protons in the nucleus and introduce the strong nuclear force to explain why nuclei do not self destruct.
Keywords
Nucleus - the central part of an atom which contains protons and neutrons
Nucleon - the term for particles in a nucleus (protons and neutrons)
Atomic (proton) number - the number of protons within a particular nucleus
Mass (nucleon) number - the total number of nucleons within a particular nucleus (protons + neutrons)
Isotopes - atoms of the same element with differing numbers of neutrons
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