key term - Molecular Orbitals

Definition

Molecular orbitals are quantum mechanical wave functions that describe the behavior of electrons in a molecule. They are formed by the linear combination of atomic orbitals, allowing electrons to be shared between atoms and creating stable molecular structures.

5 Must Know Facts For Your Next Test

1. Molecular orbitals are formed by the linear combination of atomic orbitals, following the principle of quantum mechanical wave function superposition.
2. The filling of molecular orbitals with electrons follows the Pauli exclusion principle and Hund's rule, which determine the electronic configuration of a molecule.
3. Bonding molecular orbitals have lower energy than the original atomic orbitals, while antibonding orbitals have higher energy.
4. The strength and stability of a chemical bond are determined by the number of electrons in bonding and antibonding orbitals.
5. Molecular orbital theory provides a powerful framework for understanding and predicting the properties and reactivity of molecules.

Review Questions

• Explain the process of forming molecular orbitals from atomic orbitals.
  • Molecular orbitals are formed by the linear combination of atomic orbitals. This involves the superposition of the wave functions of individual atoms, following the principles of quantum mechanics. The combination of atomic orbitals can result in the creation of bonding orbitals, which have lower energy and promote stable chemical bonds, as well as antibonding orbitals, which have higher energy and weaken or destabilize the bonds.
• Describe how the filling of molecular orbitals with electrons determines the electronic configuration and stability of a molecule.
  • The filling of molecular orbitals with electrons follows the Pauli exclusion principle and Hund's rule, which dictate the electronic configuration of a molecule. Electrons occupy the lowest energy molecular orbitals first, with no more than two electrons in each orbital and with parallel spins in degenerate orbitals. The relative number of electrons in bonding and antibonding orbitals determines the overall stability and reactivity of the molecule. A greater number of electrons in bonding orbitals compared to antibonding orbitals results in a more stable molecular structure.
• Analyze the relationship between the properties of molecular orbitals and the characteristics of chemical bonds.
  • The properties of molecular orbitals, such as their energy levels and the nature of the wave functions, directly influence the characteristics of chemical bonds. Bonding orbitals, which have lower energy, promote the formation of stable chemical bonds by facilitating the sharing of electrons between atoms. Conversely, antibonding orbitals, with higher energy, weaken or destabilize the chemical bonds. The balance between the number of electrons in bonding and antibonding orbitals determines the overall strength and stability of the chemical bond, as well as the reactivity and other physical and chemical properties of the molecule.

Related terms

Atomic Orbitals: Atomic orbitals are mathematical functions that describe the wave-like behavior of electrons in an atom. They define the regions of space where an electron is likely to be found.

Bonding Orbitals: Bonding orbitals are molecular orbitals that result in a net attractive force between atoms, leading to the formation of a chemical bond.

Antibonding Orbitals: Antibonding orbitals are molecular orbitals that result in a net repulsive force between atoms, weakening or destabilizing the chemical bond.