Final answer:
An energy diagram in molecular orbital theory indicates bond polarity by showing skewed energy levels toward the more electronegative atom, which implies an uneven electron density distribution that characterizes a polarized bond.
Step-by-step explanation:
The energy diagram in molecular orbital theory shows whether a bond is polarized by illustrating the difference in energy levels between the bonding and antibonding molecular orbitals of the two atoms involved in a bond. For a polar bond, the energy-level diagram will be skewed or tilted toward the more electronegative atom, indicating that the electrons are more closely associated with that atom, leading to electron density shift and thus, a polar bond. This shift is depicted by the alteration in energy levels of the molecular orbitals compared to the parent atomic orbitals.The filled molecular orbital diagram shows electrons occupying both bonding and antibonding orbitals. From this, one can calculate the bond order, which gives an idea of the stability and type of bond formed. Any discrepancy in the distribution of electrons between the molecular orbitals might indicate an uneven spread of electron density across the bond, revealing the polarity of the bond.