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DELHI PUBLIC SCHOOL,JAIPUR
Worksheet -1 Session -2024-25
Subject - Chemistry
Name: Class- ss... Sec... Due Date:
Topic :Chemical Bonding And Molecular Structure
Q.1. Assertion : The bond order of helium is always zero.
Reason : The number of electrons in bonding molecular orbital and antibonding molecular orbital is equal.
Q.2. Assertion : The lesser the lattice enthalpy more stable is the ionic compound.
Reason : The lattice enthalpy is greater, for ions of highest charge and smaller radii.
Q.3. Assertion : Atoms can combine either by transfer of valence of electrons from one atom to another or
by sharing of valence electrons.
Reason:Sharing and transfer of valence electrons is done by atoms to have an octet in their valence shell.
0.4. Assertion : BF3 molecule has zero dipole moment.
Reason:F is electronegative and B-F bonds are polar in nature.
Q.5. Assertion :CH;Cl, is non-polar and CCI4 is polar molecule.
Reason: Molecule with zero dipole moment is non-polar in nature.
Q.6. Assertion : Lone pair-lone pair repulsive interactions are greater than lone pair-bond pair and bond
pair-bond pair interactions.
Reason : The space occupied by lone pair electrons is more as compared to bond pair electrons.
Q.7. Assertion : In NH3, N is sp² hybridised, but angle is found to be 107°.
Reason : The decrease in bond angle is due to repulsion between the lone pair.
Q.8. Assertion : pi bonds are weaker than ¡ bonds.
Reason : pi bonds are formed by the overlapping of p-p orbitals along their axes.
Q.9. Assertion : Shape of NH3 molecule is tetrahedral.
Reason : In NH, nitrogen is sp hybridized.
Q10.The attractive force which holds the two atoms together is called achemical bond. Acovalent bond is
formed by an equal sharing of electrons. A coordinate bond is formed by unequal sharing of electrons. An
ionic bond is formed by the transfer of electrons from one atom to another. Octet rule, although very useful
but is not universally applicable. According to valence bond theory, acovalent bond is formed by
overlapping of half-filled atomic orbitals resulting ina lowering of energy and more stability. Bond order is
the number of bonds between atoms in amolecule. The higher the bond order more willbe stability and bond
dissociation enthalpy but the smaller the bond length. The polarity of acovalent bond depends upon the
difference in electronegativity. The covalent character of a bond depends upon polarising power, smaller
cation and bigger anions have higher polarising power. vSEPR theory helps to predict the shapes of
molecules.
(a) Write the electron dot structure of N20. (b) What are the ions present in CsI3?
(c) What is the correct order of repulsion bp- bp, lp-lp, and Ip bp?
(d) Draw the structure of XeOF4 on the basis of VSEPR theory.
DELHIPUBLIC SCHOOL,JAIPUR
Worksheet - 2 Session - 2024-25
Subject - Chemistry
Name: Class-.... Sec... Due Date: eee eee ese
Topic :Chemical Bonding And Molecular Structure
Q1.Write down the resonance structures of nitrous oxide.
Q2.Which out of CH;F and CH;C1 has a higher dipole moment and why?
Q3.Why HClis polar whereas the Clh molecule is non-polar?
Q4.Explain giving reasons whether BH' and H;0* willhave the same/different geometry?
Q5.0ut of peroxide ion (0: ) and superoxide ion (0:) which has larger bond length and why?
Q6. Compare the magnetic behavior, bond length and stability of C, Cz and C, 2
Q7.Read the following passage and answer the questions given below: This theory provides a simple
procedure to predict the shapes of covalent molecules. Based on the repulsive interactions of the electron
pairs in the valence shellof the atoms. The shape of a molecule depends upon the number of valence shell
electron pairs (bonded or non-bonded) around the central atom. Pairs of electrons in the valence shell repel
one another since their electron clouds are negatively charged. These pairs of electrons tend to occupy
positions in space that minimize repulsion and thus maximize distance between them. The valence shell is
such
taken as a sphere with the electron pairs localising on the spherical surface at maximum distance from one
another. A multiple bond is treated as ifit is a single electron pair and the two or three electron pairs of a
multiple bond are treated as a single super pair. Where two or more resonance structures can represent a
molecule, the VSEPR model is applicable to any such structure. The repulsive interaction of electron pairs
decrease in the order: Ip -Ip>lp -bp>bp- bp 63 lone pairs are localised on the central atom and each bonded
pair is shared between two atoms. As a result, the lone pair electrons in a molecule occupy more
space as
compared to the bonding pairs of electrons. These results in greater repulsion between lone pairs of electrons
as compared to the lone pair -bond pair and bond pair - bond pair repulsions.
1. Percentage of s-character in sp² hybrid orbital is
a) 25 b) 50 c) 33 d) 75
2. Shape of XeF4 molecule is
a) Linear b) Pyramidal c) Tetrahedral d) Square planar
3.Shape of methane molecule is
a) Pyramidal b) Tetrahedral c) Octahedral d) Square planer
4. Hybridisation involves
a) Mixing up of atomic orbitals b) Addition of an electron pairc) Removal of an electron pair d)
of orbitals Separation
5. Number of lone pair (s) in XeOF4 is/are
a) 0b) 1c) 2d) 3
