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A Short Note on Bond Order As Per The Molecular Orbital Theory

When it comes to describing bonding, the Molecular Orbital Theory incorporates the wavelike characteristics of electrons. Atomic orbitals are used in Molecular Orbital Theory to describe how atoms are linked together in bonds. The Molecular Orbital Theory provides answers to more complex questions than the Valence Bond Theory and Lewis Structures. The electrons are delocalized in the Molecular Orbital Theory. When electrons are not assigned to a specific atom or bond, this is referred to as “delocalization” (as in the case with Lewis Structures). According to molecular orbital theory, the bond order can be calculated by dividing the number of bonding electrons by the number of antibonding electrons by two. Using the concept of bond order as a measure of binding strength is a common occurrence in valence bond theories. It is called a bond when two atoms share an electron. It is possible to create single, double and triple bonds when two or more electrons are shared by the two atoms. The Schrödinger Equation can be used to estimate the probability that an electron can be found anywhere in the nucleus, despite the fact that its exact location cannot be determined. Using this equation, it is possible to predict the electron’s energy distribution and the shape of each orbital. The first five solutions to the equation for a one-electron atom are shown in the figure below. The different shades of blue and green denote different stages of the function. In this diagram, the colours blue and red represent the opposites of each other: negative and positive.

Principles of Molecular Orbital Theory

Atomic orbitals combine in molecular orbitals, which encircle the molecule. Molecular orbitals, like atomic orbitals, are wave functions that indicate the likelihood that an electron will be found in a particular part of a molecule. There can only be two electrons in each molecule’s orbital, and they must both have the opposite spin. There can only be two electrons in each molecule’s orbital, and they must both have the opposite spin. The Pauli principle, the aufbau principle, and Hund’s rule are all used to find the ground state configuration once you have the molecular orbitals and their energies in order.

Formula of Bond Order

Molecular orbital theory uses functions that describe the state of electrons in a particle to determine bond order. An orbital is a type of mathematical function. To put it another way, the orbitals represent the most likely locations of electrons in the electron cloud, which are denoted by the letters s, p, d, and f on a symbol chart. There is a specific bond energy for each orbital (s is a sphere, p is an eight-shaped figure). Depending on the bond’s geometry, we can also distinguish between bonding, antibonding, and nonbonding orbitals.

It’s important to know how many electrons are in a valence shell in order to determine bond order. This can be done by comparing the image shown below to the periodic table.

mo

S: the valence shell has the same number of electrons as the atomic number of the element (except helium, which has two valence electrons)

Valence electrons are equal to the element’s group-minus-ten number.

We should look at how electrons fill orbitals in order to get a better understanding of elements from blocks d and f.

From the most energy-efficient to the least, electrons fill the orbitals from s to f. The s-block elements each have one bonding and one antibonding orbital free for bonding, each with two electrons available. Three orbitals in the p block, five in the d block, and seven in the f block are available for bonding. In each orbital, there is a bonding and an antibonding orbital, with the bonding orbitals being filled first.

What is the formula for figuring out the order of a bond? This bond order formula can be used after you have determined the number of bonding and antibonding electrons in the system.

In chemistry, bonding electrons are divided by the number of antibonding electrons.

Bond Order of A Covalent Bond 

Molecular orbital theory describes electron distribution in molecules similar to the distribution of electrons in atomic orbitals. A molecular orbital is the area of space where a molecule’s valence electron is most likely to be found. Chemical orbitals are created mathematically by adding together atomic orbitals in a straight line (LCAO). Electron density is more likely in areas where atomic orbital wave functions are in phase, while this is less likely in areas where the waves are out of phase.

It is possible to combine two adjacent atoms’ s orbitals in a way that produces a lower-energy bonding molecular orbital in which the majority of the electron density lies directly between the nuclei. Antibonding molecular orbital with a node between the nuclei is formed as a result of the out-of-phase addition.

P orbitals’ wave function also generates two lobes with opposing phase differences. σ and σ* orbitals are formed when p orbitals overlap end to end. bonding π and π* antibonding molecular orbitals are formed by the side-by-side overlap of two p orbitals.

The number of electrons in bonding and antibonding molecular orbitals is shown in the filled molecular orbital diagram. Only electrons in bonding orbitals can participate in a bonding interaction.

Bonding and Antibonding Electrons

A molecule is held together by electrons in bonding orbitals because they are located between the nuclei of the atom.

As a result of their proximity to the nuclei, they have lower energies.

The density of electrons between the nuclei is reduced in antibonding orbitals.

In order to compensate for the increased nuclear repulsions, the molecular energy is increased.

In terms of energy, antibonding orbitals have a leg up on their bonding counterparts.

Conclusion 

When it comes to describing bonding, the Molecular Orbital Theory incorporates the wavelike characteristics of electrons.Molecular orbital theory describes electron distribution in molecules similar to the distribution of electrons in atomic orbitals.A molecule is held together by electrons in bonding orbitals because they are located between the nuclei of the atom.

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Frequently asked questions

Get answers to the most common queries related to the NEET UG Examination Preparation.

Do antibonding electrons have greater bonding than bonding electrons in molecules?

Ans. The energy of a bonding molecular orbital is always lower (more stable) than the energy of the component atomic...Read full

Why are bonding and antibonding molecular orbitals more stable than each other?

Ans. The related antibonding molecular orbital has a lower energy and so is more stable than the bonding molecular o...Read full

State about bonding electrons.

Ans. An electron involved in chemical bonding is known as a bonding electron. A chemical bond is a long-term attract...Read full

What is N2+ bond order?

Ans. 2.5

What is a MO theory limitation?

Ans. According to the MO theory, electrons are delocalized. This suggests they’re dispersed throughout the mol...Read full