Chemical Bonding and Molecular Structure

Explain the formation of a chemical bond.

Draw the Lewis structures for the following molecules and ions:

Define octet rule. Write its significance and limitations.

Write the favourable factors for the formation of ionic bond.

Discuss the shape of the following molecules using the VSEPR model:

Although geometries of NH₃ and H₂O molecules are distorted tetrahedral, bond angle in water is less than that of ammonia. Discuss.

How do you express the bond strength in terms of bond order?

Define the bond length.

Explain the important aspects of resonance with reference to the CO₃²⁻ ion.

Write the resonance structures for SO₃, NO₂ and NO₃⁻.

Although both CO₂ and H₂O are triatomic molecules, the shape of H₂O molecule is bent while that of CO₂ is linear. Explain this on the basis of dipole moment.

Write the significance/applications of dipole moment.

Define electronegativity. How does it differ from electron gain enthalpy?

Explain with the help of suitable example polar covalent bond.

Arrange the bonds in order of increasing ionic character in the molecules: LiF, K₂O, N₂, SO₂ and ClF₃.

Apart from tetrahedral geometry, another possible geometry for CH₄ is square planar with the four H atoms at the corners of the square and the C atom at its centre. Explain why CH₄ is not square planar?

Explain why BeH₂ molecule has a zero dipole moment although the Be–H bonds are polar.

Which out of NH₃ and NF₃ has higher dipole moment and why?

Describe the change in hybridisation (if any) of the Al atom in the following reaction. AlCl₃ + Cl⁻ → AlCl₄⁻

Is there any change in the hybridisation of B and N atoms as a result of the following reaction? BF₃ + NH₃ → F₃B.NH₃