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Topic notes



Nature of science relevant to atomic theory

  • Improvements in instrumentation allowed chemists to obtain more evidence to support ideas or to refute ideas (paradigm shift)
  • Examples of paradigm shifts during the development of the atomic theory; one example were the findings by Rutherford in his gold foil experiment
  • Experimental evidence to support theories—emission spectra provide evidence for the existence of energy levels.



Atomic models

Thomson cathode ray experiment
Phet Rutherford scattering experiment investigation
Rutherford experiment RSC video on mass spectrometry
Build an atom Phet build an atom
carbon 14 decay

Electromagnetic spectrum

a small applet: shows the whole spectrum and how frequency and wavelength change across it.

Below is a diagram of an absorption spectra which is a continuous spectrum with discrete black lines/missing frequencies where absorption has occurred.
external image 320px-Fraunhofer_lines.svg.png

Emission spectra

flame tests Line emissions and absorptions
How a line spectrum is formed?
Difference between absorption and emission[[|More on that difference]]
another hydrogen spectra shows the transition of electrons.
a lot of emission spectra
more spectra more emission spectra of some common metals e.g. alkali metals and also shows how we see the line emission spectrum


Atomic orbitals: chlorine orbitals use Firefox
gallery of orbitals including hybridized ones
Aufbau: Aufbau animation

Mass spectrometer

from RSC - very good
video on YouTube mass spectrometryfrom Royal Society of Chemistry
and a mass spectroscopy tutorial
More mass spectrometry videos:


electron configurations: aufbau method

lesson activities

Khan academy

Links to IGCSE Edexcel chemistry