BRAINCAKEAtomic Structure
Revision notes for Atomic Structure in Edexcel Chemistry (8CH0). 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.
- Discovery of Atomic Structure1897: J.
- Structure of the AtomAn atom is made of three sub-atomic particles: protons, neutrons and electrons.
- Atomic Number and Mass NumberThe atomic number is the number of protons in the nucleus.
- IsotopesIsotopes are atoms of the same element with the same number of protons and different number of neutrons Hydrogen has three isotopes: hydrogen-1 (1…
- Relative Isotopic MassThe relative isotopic mass is the mass of an atom of an isotope compared to 1/12th the mass of a C-12 atom.
- Relative Atomic MassThe relative atomic mass is the weighted mean mass of an atom of an element compared to 1/12th the mass of a carbon-12 atom which has a mass of 12.
- Mass SpectrometerA mass spectrometer measures the mass of atoms and molecules The mass spectrometer can be used to experimentally measure the percentage abundances…
- Relative Atomic Mass from a Mass SpectrometerYou can determine the relative masses of isotopes from a mass spectrum of the element.
- Relative Molecular Mass from a Mass SpectrometerThe structure of covalent compounds can be analysed by a mass spectrometer.
- Quantum ShellsElectrons exist in well-defined energy levels called quantum shells.
- OrbitalsAn orbital is a region in space where there is a 95% chance of finding the electron.
- Electronic ConfigurationsOrbitals fill in order of increasing energy.
- Predicting Electronic ConfigurationPauli Exclusion Principle and Hund's Rule The Pauli exclusion principle states that two electrons may occupy the same orbital only if they have…
- Energy Levels and Emission SpectraWhen atoms in a gaseous state are given energy by either heating or passing an electric current through them electrons move to a higher energy level.
- 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…
- Successive Ionisation EnergiesThe first ionisation energy is the least endothermic as energy is needed to remove an electron from a neutral atom.
- The Energy of an ElectronThe ionisation energy of an atom is the energy needed to remove an electron, so it is a measure of how strongly that electron is held in its orbital.
- Ionisation Energy across a PeriodIonisation energy depends on: the nuclear charge which depends on the number of protons the shielding, energy of the quantum shell and distance from…
- Ionisation Energy Down a GroupAs we go down a group, the nuclear charge increases as the number of protons increase but this is outweighed by the increase in shielding and the…