Molecules and colour Flashcards
1
Q
What type of compounds absorb electromagnetic energy?
A
Organic Compounds
2
Q
Why are most organic compounds colourless?
A
The wavelength of light absorbed lies outside the visible range on the electromagnetic spectrum.
3
Q
HOMO
A
Highest occupied molecular orbital.
4
Q
LUMO
A
Lowest unoccupied molecular orbital
5
Q
What is higher HOMO or LUMO
A
LUMO
6
Q
Conjugated system
A
Relatively large number of carbon atoms with multiple double bonds and benzene rings. The pi and sigma bonds must be alternating
7
Q
Explanation of coloured organic compounds.
A
Large conjugated system causes smaller gap between HOMO and LUMO, hence the energy gap is equivalent to the energy of a colour in EM spectrum. This colour is absorbed by the compound and the complementary colour is observed.
