Question

. The valence bond theory explains the shape, the formation and directional properties of bonds in
polyatomic molecules like CH4, NH3 and H2O etc, in terms of
a) overlapping of atomic orbitals
b) hybridisation of atomic orbitals
c) Both (a) and (b)
d) None of the above

Answer 1

Answer:

The valence bond theory is not perfect. It has its own sets of limitations. It fails to answer the energies of the molecules. It explains the shapes of the simple molecules and also the overlapping and hybridization of the atomic orbitals that results in the formation of chemical bonds.

Answer 2

Answer:

The correct answer is option (c)

(c) Both (a) and (b)

Explanation:

• The covalent bond formation and the electronic structure of molecules was explained by the Valence bond theory.
• This theory was proposed by Heitler and London.
• The shape of the molecules, overlapping of atomic molecules and the hybridisation of the atomic molecules are explained by the Valence bond theory.
• Two atoms of the valence shell atomic orbitals have the unpaired electrons therefore the overlapping of electrons in valence shell occurs. This result in the formation of Covalent bond.
• CH₄, NH₃ and H₂O are polyatomic molecules. In these molecules the geometry and the bond formation of the molecules are important.
• The shape of  CH₄ molecule is tetrahedral, the shape of NH₃ is pyramidal and the shape of H₂O molecule is bent.
• The valence bond theory explains the shape, the formation and directional properties of bonds in polyatomic molecules like CH₄, NH₃ and H₂O etc, in terms of overlapping and hybridisation of the atomic molecules.

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