Question

The formula $\frac{\mathrm{Total}\mathrm{valence}\mathrm{electron}}{8}$ given for hybridization is applicable or not? if not find the limitations and solution for this with example.

Answer 1

Hybridization:

• In chemistry, hybridization is the idea of combining two atomic orbitals to create a brand-new category of hybridized orbitals.
• Typically, this mixing creates hybrid orbitals with completely distinct energies, morphologies, etc.
• In hybridization, the same-energy level atomic orbitals are primarily involved.
• However, assuming they contain equal energy, both completely filled and partially filled orbitals can participate in this process.

Analyzing the given formula:

• $\mathrm{Hybridization}=\frac{\mathrm{total}\mathrm{valence}\mathrm{electron}}{2}$
• The above-mentioned formula is completely wrong as during calculating hybridization other factors must be also taken into account.
• These factors include the number of monovalent atoms surrounding the main atom, the cation's positive charge and, the Negative charge on the anion
• Thus this formula is not applicable.
• If the valence electron count exceeds eight, then the formula is
• $\mathrm{Hybridisation}=\frac{1}{8}\mathrm{x}(\mathrm{V}+\mathrm{X}-\mathrm{C}+\mathrm{A})$
• If the valence electron count does not exceeds eight, then the formula is
• $\mathrm{Hybridization}=\frac{1}{2}\mathrm{x}(\mathrm{V}+\mathrm{X}-\mathrm{C}+\mathrm{A})$

Limitations of the given formula:

• For all compounds that have the same atom or ion in a central atom the hybridization ought to be the same but it is not the case.
• For example, all the compounds of Xenon have different hybridizations even though the central atom is the same.
• 
• All compounds having an odd number of atoms in valence at the central atom would have fractional hybridization which would be not possible.

The formula for hybridization:

• According to the following formula, hybridization is:
• $\mathrm{H}=\left(\frac{1}{2}\right)\times (\mathrm{V}+\mathrm{X}-\mathrm{C}+\mathrm{A})$ (as the value does not exceed the eight)
• Where: $\mathrm{V}$ is the number of valence electrons in the centre atom
• $\mathrm{X}$ is the number of monovalent atoms surrounding the main atom.
• $\mathrm{C}$ is the cation's positive charge.
• A negative charge on the anion equals A.
• For example Hybridization of ${\mathrm{PCl}}_5$
• $$\begin{gathered} {\mathrm{PCl}}_5:\mathrm{H}=\frac{1}{2}[5+5–0+0] \\ \mathrm{H}=5 \end{gathered}$$
• Hybridisation of ${\mathrm{PCl}}_5$: ${\mathrm{sp}}^3\mathrm{d}$