• Describe how the model of the atom has changed over the years, and how it continues to do so.

• Understand that scientific knowledge is always evolving.

• Describe how new theories are accepted by scientists.

Week 1

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Rutherford’s gold-leaf experiment

Week 1

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• Describe protons, neutrons and electrons.

• Describe the distribution of mass and charge in an atom.

• Describe the contribution of protons and neutrons to the nucleus in terms of atomic number and mass number.

• Explain the term isotopes.

• Deduce the atomic structure in atoms and ions.

Week 1

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An isotope of beryllium

Week 1

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Week 1

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Symbol for an isotope

• Explain why 12C is used as the standard measurement of relative mass.

• Define the terms relative isotopic mass and relative atomic mass.

• Calculate relative atomic masses.

• Work out relative molecular masses and relative formula masses.

Week 1

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Carbon-12: the standard for measuring atomic masses

Week 1

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