U3-1-2 - Hybrid Orbitals Flashcards
Two atomic orbitals combine to make ___ molecular orbitals.
two
What is the difference between bonding and antibonding orbitals?
Antibonding orbitals are higher in energy.
How do sigma bonds form?
End on overlap of atomic orbitals
How do pi bonds form?
Side on overlap of atomic orbitals.
Which bonds are stronger, sigma or pi?
Sigma (better overlap of atomic orbitals)
How do you count the number of sigma and pi bonds in a molecule?
All single bonds are sigma.
In double/triple bonds, first bond is sigma, the rest are pi.
Type of hybridisation found in alkanes
sp3
Type of hybridisation found in alkenes and aromatic rings
sp2
Type of hybridisation found in alkynes (C≡C)
sp
Bond angle associated with sp3 hybridisation
109.5° (tetrahedral geometry)
Bond angle associated with sp2 hybridisation
120° (trigonal planar geometry)
Bond angle associated with sp hybridisation
180° (linear geometry)
Explain how sp3 hybrid orbitals form
One s and three p orbitals mix to form four degenerate sp3 atomic orbitals
Explain how sp2 hybrid orbitals form
One s and two p orbitals mix to form three degenerate sp2 atomic orbitals
Explain how sp hybrid orbitals form
One s and one p orbital mix to form two degenerate sp atomic orbitals
Which orbitals overlap to form sigma bonds in alkanes?
sp3 hybrid orbitals (overlap end on)
Which orbitals overlap to form pi bonds in alkenes and aromatic rings?
unhybridised 2p orbitals (overlap side on)
Which hybrid orbitals overlap to form sigma bonds in aromatic rings?
sp2 hybrid orbitals (overlap end on)
Molecular formula for benzene
C6H6
Benzene structure (skeletal)
Benzene structure (full)
State the feature that provides stability to aromatic rings.
Delocalised (pi) electrons
Which orbitals overlap to form pi bonds in aromatic rings?
Unhybridised p orbitals (overlap side on)
