Which of the following statements are true?

a. Antibonding orbitals are higher in energy than bonding orbitals (if all orbitals are created from the same atomic orbitals).

b. Electrons cannot occupy an antibonding orbital.

c. The probability is 100% for finding an electron at the nucleus in a π∗ orbital.

d. s orbitals can make only σ or σ∗ molecular orbitals.

Option a and d are true

Explanation:

Antibonding orbitals are higher in energy than bonding orbitals this is due to the decrease in electron density between the nuclei.

An antibonding orbital is an atomic or molecular orbital whose energy increases as its constituent atoms are brought closer together - thus generating a repulsive force that hinders bonding.

Electrons cannot occupy an antibonding orbital is false because if the bonding orbitals are filled according to Pauli exclusion principle, then any additional electrons will occupy antibonding orbitals.

The probability is 100% for finding an electron at the nucleus in a π * orbital is false.

Pi orbital (π orbital), is an antibonding molecular orbital and is formed by the overlapping of two bonded nuclei. Here we see one nodal plane passing through the two nuclei, like pi bonds.

s orbitals can make only 'σ' a lower energy molecular orbital or 'σ∗' a higher energy molecular orbitals in adjacent atoms when they overlap. This is true