Atomic structure Revision - AQA Chemistry 7405

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15 objective pages available

Fundamental particles4 objectives

Explain that scientific understanding of atomic structure has developed over time.
State the relative charge and relative mass of protons, neutrons and electrons.
Describe an atom as a nucleus containing protons and neutrons surrounded by electrons.
Use particle properties to compare atoms, ions and isotopes.

Mass number, isotopes and mass spectrometry6 objectives

Determine the numbers of protons, neutrons and electrons in atoms and ions from mass number, atomic number and charge.
Explain the existence of isotopes using different neutron numbers.
Describe the principles of a simple time-of-flight mass spectrometer: ionisation, acceleration, ion drift, detection and data analysis.
Interpret simple mass spectra of elements.
Calculate relative atomic mass from isotopic abundance data for mononuclear ions.
Report isotope and mass-spectrometry calculations to an appropriate number of significant figures.

Electron configuration and ionisation energy5 objectives

Write electron configurations of atoms and ions up to atomic number 36 using shells and s, p and d subshells.
Define first ionisation energy.
Write equations for first and successive ionisation energies.
Explain how first and successive ionisation energies provide evidence for shells and subshells.
Interpret ionisation energy data for Period 3 and Group 2 elements.

Atomic modelIsotopeProtonElectronatomnucleusionNeutronisotopeneutron numberIonisationTime‑of‑Flight Mass Spectrometer

Use a Timeline of Key Experiments: Explain clearly by create a visual timeline that lists the major experiments (e.g., Thomson’s cathode ray tube, Rutherford’s gold foil, Bohr’s hydrogen spectrum) and the conclusions they led to. When answering exam questions, refer to the relevant experiment to justify why the atomic model changed. Link the point to Fundamental particles, then state the evidence, calculation, mechanism, observation, or conclusion required by the question.
Understanding Particle Charges and Masses: Explain clearly by memorize the relative charges and masses of protons, neutrons, and electrons: Protons have a relative charge of +1 and a relative mass of 1, neutrons have a relative charge of 0 and a relative mass of 1, and electrons have a relative charge of -1 and a relative mass of 1/1836. Link the point to Fundamental particles, then state the evidence, calculation, mechanism, observation, or conclusion required by the question.

Misunderstanding Atomic Structure Development: To correct this, students should study the progression of atomic models, from Dalton's solid sphere model to Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's model, noting how each contributed to our current understanding. For example, the formula for atomic structure development can be summarized as: 'Historical models + experimental evidence = current atomic theory'. This shows how scientific understanding evolves with new discoveries.
Relative Charge Confusion: Remember that protons have a relative charge of +1, neutrons have a relative charge of 0, and electrons have a relative charge of -1. To clarify: Protons: +1, Neutrons: 0, Electrons: -1.

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