Chapter 4: Chemical Bonding and Molecular Structure

(i) A covalent bond is formed by the overlapping of atomic orbitals. The direction of overlapping gives the direction of the bond.

(ii) In a water molecule, the oxygen atom is sp3 hybridized and has two lone pairs of electrons.

(iii) In the ethyne molecule, both the carbon atoms are sp hybridized. The two sp hybrid orbitals of both the carbon atoms are oriented in the opposite direction forming an angle of 180°.

when a positively charged ion forms a bond with a negatively charged ions and one atom transfers electrons to another. An example of an ionic bond is the chemical compound Sodium Chloride (NaCl).

The difference between an ionic bond and covalent bond is that An ionic bond essentially donates an electron to the other atom participating in the bond, while electrons in a covalent bond are shared equally between the atoms.

The ionic character is greater in the molecules that have the greatest electronegativity difference because the electron pair shifts toward a more electronegative atom, increasing the ionic character.

Thus, the ionic character order will be:

C-H<N-H<O-H< F-H

Carbonate ion is present in the form of a resonating hybrid structure. These structures are equivalent. Resonance all 3 C-O bonds get a double character in one of the resonating structures.

Thus, all the bonds are equivalent and have equal length hence carbonate ion cannot be represented by a single Lewis structure.

The hybridization of Carbon 1 is sp, carbon 2 is sp, carbon 3 sp2, carbon 4 is sp3 and carbon 5 is sp2.

The triple bond has 2 pie bonds and one sigma bond.

Each double bond has one sigma and one pie bond.

Every single bond is a sigma bond.

Thus, the total number of sigma bonds is 11 and pie bonds are 4.

BeCl₂ has a linear structure

HOCl is also non-linear in structure.

H₂O has a V-shaped structure.

Cl₂O has a V-shaped structure.

(i); XH4, H3Y, and HZ

Hydrogen has only one electron in its outermost shell it shares one electron to form a covalent bond or accepts or donates one electron to form an ionic bond.

(ii) The compound HZ has a linear shape and the difference in the electronegativity of Hydrogen and element Z is maximum.

In compound BCl₃, Boron has sp2-hybridisation and the shape is Triangular Planar.

In methane CH₄, Carbon has sp3 -hybridization and shape are Tetrahedral.

In carbon dioxide CO₂, carbon has sp-hybridisation and shape is Linear.

In ammonia NH₃, nitrogen has sp3-hybridisation and shape is Pyramidal.

Carbonate ion is present in the form of a resonating structure. These structures are equivalenting to nature. Resonance all 3 C-O bonds get a double character in one of the resonating structures.