Hybridization PT2

What is constructive overlap in molecular orbitals?

It concentrates electron density between the nuclei, resulting in bonding (ΦB).

What is non-constructive overlap in molecular orbitals?

It removes electron density between nuclei, forming a node/nodal plane, resulting in antibonding orbital (ΦA).

Which has higher energy: bonding or antibonding orbital?

The antibonding orbital (ΦA) is higher in energy than the bonding orbital (ΦB).

How is an antibonding orbital usually indicated?

With an asterisk (*).

What is required for two atomic orbitals to combine into a sigma molecular orbital?

They must be symmetrical in sign about the bond axis and have similar energies.

Can unlike atomic orbitals form sigma molecular orbitals?

Yes, if they are symmetrical and of similar energy (e.g., s and pz).

Why can px and py not form sigma bonds?

They are antisymmetric with respect to the bond axis (change sign across the axis).

What type of bond can px and py form?

A pi (π) bond via lateral overlap of p orbitals.

What is the difference between π bonding and π* antibonding molecular orbitals?

π bonding accumulates electron density between nuclei; π* antibonding has a nodal plane and higher energy.

How do the energies of π and π* orbitals compare to atomic p orbitals?

π bonding is lower in energy; π* antibonding is higher by the same amount.

How do px and py orbital energies compare?

px and py have equal energy; px and py also have equal energy.

What is a delta (δ) molecular orbital?

Formed by "face-to-face" overlap of two d orbitals.

What are the energy and electron density differences between bonding and antibonding molecular orbitals?

Bonding MOs concentrate electrons between nuclei (lower energy); antibonding MOs remove electrons from between nuclei (higher energy).

Which orbitals form σ molecular orbitals?

Any atomic orbitals symmetrical with respect to the bond axis.

Which orbitals form π molecular orbitals?

Any atomic orbitals antisymmetrical with respect to the bond axis.

What information do molecular orbital diagrams provide?

(1) Bond order, (2) Number of unpaired electrons, (3) Energy levels.

What does bond order indicate?

Whether the bond between atoms is single, double, or triple.