MCQs on Overlapping and Bonds

The overlap of atomic orbitals produces an increase in electron charge density between the atomic nuclei. The increased negative charge density holds the positively charged atomic nuclei together, and constituents the covalent bond. A covalent bond is a region of high electron charge density produced by the overlap of the atomic orbitals of two atoms. The greater is the extent of overlap of orbitals, greater is the strength of the resulting bond. The shape of the molecule is determined by the direction in which the overlapping orbitals point. The overlapping orbitals resulting in covalent bonds may be pure or hybrid. A hybrid orbitals is one of a set of identical orbitals produced by the combination of different types of atomic orbitals.

1. Which of the following at ordinary temperature and pressure exists as a linear polymer due to extensive hydrogen bonding?

  1. H2O
  2. HCl
  3. HF
  4. NH3

Answer: (c)

2. The shape of SF3Cl3 molecule is

  1. triangle bi-pyramidal
  2. cubic
  3. octahedral
  4. tetrahedral

Answer: (c)

3. The structure of CH2=C=H2 is

  1. linear
  2. planar
  3. non-planar
  4. has several reasoning structure

Answer: (a)

4. Which is the correct arrangement of the molecules based on dipole moments?

  1. BF3 > NF3 > NH3
  2. NF3 > BF3 > NH3
  3. NH3 > BH3 > NF3
  4. NH3 > NF3 > BF3

Answer: (d)

5. When two ice cubes are pressed over each other, they unite to form one cube. Which of the following forces is responsible to hold them together?

  1. Ionic interaction
  2. covalent attraction
  3. van der waals forces
  4. hydrogen bond formation

Answer: (d)

6. Which of the following is diamagnetic?

  1. Superoxide ion
  2. carbon molecule
  3. unipositive ion of nitrogen molecule
  4. oxygen molecule

Answer: (b)

7. A molecule of fluorine is formed by

  1. the axial p-p orbital overlap
  2. the sidewise p-p orbital overlap
  3. the axial s-s orbital overlap
  4. the axial s-p orbital overlap

Answer: (d)

8. Which one of the following molecules has the smallest bonds?

  1. NH3
  2. PH3
  3. H2O
  4. H2Se

Answer: (d)

9. Polarity in a molecule and hence the dipole moment depends primarily on electronegativity to the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment?

  1. CO2
  2. HI
  3. H2O
  4. SO2

Answer: (c)

10. The electron configuration of the outermost shell of the most electronegative element is

  1. 2s22p2
  2. 3s23p5
  3. 4s24p5
  4. 5s25p5

Answer: (a)

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