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Colour theory - Coggle Diagram
Colour theory
colours of molecules
Molecules with alternating single and double bonds have conjugated systems, as well as aromatic compounds
A conjugated system is a system of adjacent unhybridised p orbitals that form a molecular orbital over a number of carbon atoms
Molecules containing conjugated systems have chromophores, which are groups of atoms in molecules that are responsible for absorption of light in the visible spectrum
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The highest bonding molecular orbital containing electrons is called the highest occupied molecular orbital HOMO
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When light is absorbed in the visible region, the compound will show the complementary colour to the colour absorbed
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Atomic spectroscopy
In Atomic spectroscopy, the concentration of an element in a sample is related to the intensity of light emitted or absorbed
In emission spectroscopy, the intensity of light emitted at different wavelengths is measured
In absorption spectroscopy, the intensity of absorbed light at different wavelengths is measured
An emission spectrum is a black background with coloured lines, whereas an absorption spectrum is a coloured background with black lines
In emission spectroscopy, electrons are promoted to the excited state, but this state is unstable, so electrons soon fall back down. When this happens, a packet of energy (quantum) or a photon is released for each electron transition, which produces a line in the emission spectrum
In a flame test, heat energy is used to promote electrons to the excited state.