Answer:
A) The sigma1s orbital is filled, and the sigma1s* orbital is empty.
Explanation:
In the formation of the H2 molecule, the two hydrogen atoms combine to form a molecular orbital diagram. The sigma1s orbital, which is a bonding orbital resulting from the overlap of the two 1s atomic orbitals, is filled with the two electrons from the hydrogen atoms. On the other hand, the sigma1s* orbital, which is an anti-bonding orbital, remains empty as it is higher in energy and not occupied by any electrons in the H2 molecule. This configuration reflects the stability and bonding nature of the sigma1s orbital compared to the sigma1s* orbital in the molecular orbital theory of the H2 molecule.
