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Atomic Structure

AQA AS-level ChemistryTopic 1 of 1322 lessons

Revision notes for Atomic Structure in AQA Chemistry (7404). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.

  1. Discovery of the Atom1661 Robert Boyle proposed that some substances could not be made simpler 1803 Dalton proposed that elements were made of atoms that could not be…
  2. Structure of the AtomAtoms are made of sub-atomic particles called electrons, protons and neutrons.
  3. Relative Mass and Relative ChargeAn atom consists of a nucleus which contains two types of subatomic particles - protons and neutrons.
  4. Atomic Number and Mass NumberThe atomic number is the number of protons in the nucleus.
  5. IsotopesIsotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
  6. Isotopes of CarbonCarbon has three isotopes: carbon-12, carbon-13 and carbon-14 carbon-12 carbon-13 carbon-14 symbol 12 C 6 13 C 6 14 C 6 protons 6 6 6 neutrons 6 7 8…
  7. Electrons1913 Niels Bohr proposed that electrons orbit in shells at fixed distances from the nucleus and with fixed energies.
  8. Electron ShellsYou can never say where an electron is at any given moment.
  9. The Mass SpectrometerA mass spectrometer can be used to experimentally measure the percentage abundances of isotopes in a sample of an element.
  10. Time of Flight Mass SpectrometerThere are different types of mass spectrometer.
  11. Mass Spectra of ElementsThe mass spectrum of an element shows a separate peak for each isotope.
  12. Low Resolution Mass SpectrometryLow resolution mass spectrometryshows the m/z ratio or mass-to-charge ratio of each isotope and the corresponding percentage abundances.
  13. Mass Spectrometer in SpaceSpace probes such as the Mars rover curiosity have mass spectrometers to analyse rock samples and identify which elements they are composed of and…
  14. Quantum MechanicsThe Shroedinger wave equation describes the atom mathematically.
  15. Energy LevelsElectrons in different shells have different amounts of energy (shells).
  16. Atomic OrbitalsAn electron is considered to be a cloud of negative charge that fills a volume in space called an atomic orbital.
  17. Order of filling orbitalsNo atomic orbital can hold more than two electrons.
  18. Electron ConfigurationOrbitals fill in order of increasing energy.
  19. First Ionisation EnergyThe First Ionisation Energy is the energy needed to remove one electron from each atom of one mole of atoms in their gaseous state to form one mole…
  20. Successive Ionisation EnergiesThe first ionisation energy is the least endothermic as energy is needed to remove an electron from a neutral atom.
  21. Trends in First Ionisation Energy Across a PeriodFirst Ionisation energies increase across a period.
  22. Trends in Ionisation Energy Down A GroupIonisation energy decreases down a group.

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