Unit 3 Topic 2 ✓ Flashcards
Organic chemistry: Molecular orbitals
What is a Sigma molecular orbital?
A sigma molecular orbital is formed by the end-on overlap of two atomic orbitals along the axis of a covalent bond
NOTE: Sigma bonds are stronger than Pi bonds
What is a Pi molecular orbital?
A pi molecular orbital is formed by side on overlap of two parallel atomic orbitals that are perpendicular to the axis of the covalent bond
NOTE: Pi bonds are weaker than Sigma bonds
What does Constructive interference between two wave functions result in?
(Think constructive feedback is positive)
Constructuve interference between two wave functions results in a Bonding molecular orbital which is in a lower energy, more stable state because the two nuclei are held within the area of electron density
What does Destructuve interference between two wave functions result in?
(Destructive -> negative)
Destructive interference bwteen two wave functions results in an Anti-bonding molecular orbital which has a region of zero electron probability between nuclei. Its in a higher energy, less stable state
What is Electronegativity?
Electronegativity is the attraction of an atom involved in a bond for the bonding pair of electrons
What is Hybridisation?
Hybridisation is when atomic orbitals mix within an atom to generate new, hybrid orbitals
What is an Alkene?
An alkene is an unsaturated molecule that contains at least one carbon to carbon double bond
What is a Conjugated system?
A system where there is alternating double and single bonds
What is HOMO?
HOMO is the highest occupied molecular orbital, it contains electrons with the highest energy
What is LUMO?
LUMO is the lowest unoccupied molecular orbital, it contains no electrons and has the least energy
What is a Chromophore?
A chromophore is a group of atoms in an organic molecule that absorbs photons of light in the visible part of the spectrum
