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Federal (FBISE) · Chapter test · Free

1st Year Chemistry Chapter 3 Test03. Chemical Bonding

30 marks · 40 minutes · 21 questions. Covers: 03. Chemical Bonding.

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1st Year Chemistry Chapter 3 Test

1st Year · Chemistry · Federal (FBISE)

Name: ____________Roll No: ________Class/Section: ________Date: ________Total marks: 30Time: 40 minutes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

  1. Which type of bonding involves a "sea of delocalized electrons"?
    1. Covalent
    2. Ionic
    3. Metallic
    4. Hydrogen
  2. A greater difference in electronegativity between two atoms results in a bond that is:
    1. More covalent
    2. Nonpolar
    3. Less ionic
    4. More polar
  3. The difference in electronegativity greater than 1.8 indicates:
    1. Covalent bond
    2. Ionic bond
    3. Metallic bond
    4. Hydrogen bond
  4. The structure of SO₂ molecule is:
    1. Linear
    2. Trigonal planar
    3. Bent
    4. Octahedral
  5. The shape of CO₃²⁻ ion is:
    1. Trigonal planar
    2. Linear
    3. Tetrahedral
    4. Trigonal pyramidal
  6. The molecular orbital of low energy is called:
    1. Bonding molecular orbital
    2. Antibonding orbital
    3. Non-bonding orbital
    4. Excited orbital
  7. Which chlorine compound has bonding that can be described as ionic with some covalent character?
    1. NaCl
    2. MgCl2MgCl_2
    3. AlCl3AlCl_3
    4. SiCl4SiCl_4
  8. VSEPR theory is used to determine:
    1. Molecular weight
    2. Shape and bond angle of molecules
    3. Melting point
    4. Type of bond
  9. A sigma (σ) bond is formed by:
    1. Parallel overlap of orbitals
    2. Overlap of d-orbitals only
    3. Lateral overlap of orbitals
    4. Head-on overlap of orbitals
  10. The molecular geometry of NH₃ is:
    1. Trigonal planar
    2. Trigonal pyramidal
    3. Linear
    4. Bent

Q2. Short questions (Attempt any 6 of 8 · 6 × 2 = 12)

  1. Why is CO₂ a nonpolar molecule even though it has polar C=O bonds?
  2. Define polar covalent bond.
  3. What are instantaneous dipole-induced dipole forces?
  4. Define dipole moment.
  5. Explain the term "bond pair" and "lone pair".
  6. What is the relationship between electronegativity difference and bond energy?
  7. Why is a sigma bond stronger than a pi bond?
  8. Explain the formation of H₂ molecule using VBT.

Q3. Long questions (Attempt any 2 of 3 · 2 × 4 = 8)

  1. Energies of orbitals can be explained by Molecular orbital theory. It has been observed that in case of Nitrogen molecule σ2px is higher in energy than π 2py and π 2pz: (a) Draw molecular orbital energy diagram for nitrogen molecule.(b) Give reason why the σ 2px energy is greater than π2py and π2pz.
  2. Explain sp, sp², and sp³ hybridization with suitable examples and orbital diagrams.
  3. The table shows the atomic number and boiling points of some noble gases.GasheliumneonargonkryptonXenonAtomic number−12−110−118−136−154Boiling point / ∘C−253−246−186−152−107 \begin{array}{|l|c|c|c|c|c|} \hline\text{Gas} & \text{helium} & \text{neon} & \text{argon} & \text{krypton} & \text{Xenon} \\ \hline \text{Atomic number} & -12 & -110 & -118 & -136 & -154 \\ \hline \text{Boiling point / }^\circ\text{C} & -253 & -246 & -186 & -152 & -107 \\ \hline \end{array} (a) Explain this trend in boiling points. (b) Xenon forms a number of covalently bonding compounds with fluorine. (1) Draw a dot- and- cross diagram for xenon tetrafluoride, XeF₄. (2) Suggest a shape for XeF₄. Explain why you chose this shape.