Molecular Orbitals Flashcards
What does covalent bonding between atoms involve?
The overlap of atomic orbitals (s, p orbitals) to form molecular orbitals (sigma, π). The attraction of positive nuclei to negative electrons occupying molecular orbitals is the basis of bonding between atoms.
How are molecular orbitals formed?
By linear combinations of atomic orbitals.
How many electrons can each molecular orbital hold?
2
How is a bonding molecular orbital made in a molecule?
By adding the mathematical functions for the atomic orbitals that come together to form the molecule.
Why is it called a bonding molecular orbital?
The electrons in this orbital spend most of their time in the region directly between the nuclei.
Why is it called a sigma bond?
It looks like an s-orbital when viewed along the bond axis.
How is an antibonding orbital made in a molecule?
By subtracting one function from the other.
Why is it called an antibonding molecular orbital?
The electrons in this orbital spend most of their time away from the region between the two nuclei.
How is antibonding orbitals denoted?
With a star, i.e. pi star (π*)
How are electrons added to molecular orbitals?
One at a time, starting with the lowest energy molecular orbital.
How are sigma bonds formed?
By end-on overlap of atomic orbitals. This is either by;
- s orbital + s orbital
- s orbital + p orbital
- p orbital + p orbital
How are pi bonds formed?
By lateral overlap of p-orbitals.
Why are the called pi bonds?
They look like p-orbitals when viewed along the line of the bond axis.
What is hybridisation?
The process of mixing atomic orbitals within an atom to generate a set of new atomic orbitals called hybrid orbitals.
What is sp³ hybridisation?
When carbon forms single bonds (alkanes), one of the 2s electrons is promoted to a higher energy 2p orbital. The one 2s and the three 2p orbitals combine to make four equivalent orbitals called sp³ hybrid orbitals.
