Mot hybridization, structure and molecule hydrogen bonding
Answers
When highly electronegative elements like nitrogen, oxygen, flourine are attached to hydrogen to form covalent bond, the electrons of the covalent bond are shifted towards the more electronegative atom. Thus, partial positive charge develops on hydrogen atom which forms a bond with the other electronegative atom. This bond is known as hydrogen bond and it is weaker than the covalent bond. For example, in HF molecule, hydrogen bond exists between hydrogen atom of one molecule and fluorine atom of another molecule.
Molecular Orbital Theory is a method developed at the beginning of the twentieth century by F. Hund and R. S. Mulliken to describe the structure and properties of different molecules.
What are Molecular Orbitals?
The space in a molecule in which the probability of finding an electron is maximum can be calculated using the molecular orbital function. Molecular orbitals are basically mathematical functions that describe the wave nature of electrons in a given molecule.
These molecular orbitals can be constructed via the combination of hybridized orbitals or atomic orbitals from each atom belonging to the specific molecule. Molecular orbitals provide a great model via the molecular orbital theory to demonstrate the bonding of molecules.
Linear Combination of Atomic Orbitals
Molecular orbitals can generally be expressed through a linear combination of atomic orbitals (abbreviated to LCAO). These LCAOs are useful in the estimation of the formation of molecular orbitals in the bonding between the atoms that make up a molecule.
The Schrodinger equation used to describe electron behavior for molecular orbitals can be written in a method similar to that for atomic orbitals.
Types of Molecular Orbitals
There exist three primary types of molecular orbitals that are formed from the linear combination of atomic orbitals. These types of orbitals are also described in the molecular orbital theory. These types of molecular orbitals are detailed below.
1. Anti-Bonding Molecular Orbitals
The electron density is concentrated behind the nuclei of the two bonding atoms in anti-bonding molecular orbitals. This results in the nuclei of the two atoms being pulled away from each other. These kinds of molecular orbitals weaken the bond between two atoms.
2. Non-Bonding Molecular Orbitals
In the case of non-bonding molecular orbitals, due to a complete lack of symmetry in the compatibility of two bonding atomic orbitals, the molecular orbitals formed have no positive or negative interactions with each other. These types of molecular orbitals do not affect the bond between the two atoms.
Molecular Orbital Theory (MOT) Features
The features of the Molecular orbital theory are provided below.
During the filling of electrons into molecular orbitals, the orbitals with the lowest energy levels are always the first to be filled. This selective filling of lower energy orbitals is commonly referred to as the Aufbau Principle.
In the molecular orbital theory, each of the molecular orbitals formed can only accommodate up to two electrons that have opposite spin. This is also called the Pauli Exclusion Principle.
When two molecular orbitals have the same energy levels, electron pairing can only occur when both of these orbitals have one electron. This rule is often called Hund’s rule.
The molecular orbitals like atomic orbitals are filled in accordance with the Aufbau principle, Pauli’s exclusion principle, and the Hund’s rule.
The energy levels of bonding molecular orbitals are always lower than those of anti-bonding molecular orbitals. This is because the electrons in the orbital are attracted by the nuclei in the case of bonding MOs whereas the nuclei repel each other in the case of the ant
