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Quiz – Covalent bonding and Lewis structures

Covalent bonding is a fundamental concept in chemistry that explains how atoms share electrons to form molecules. Molecular substances can be represented using Lewis structures. Test your understanding of Lewis structures and covalent compounds with this quiz.

Your turn – covalent bonding and Lewis structures

  1. Draw the Lewis structures of the following molecules:
    1. \(\ce{SO}_{3}\)
    2. \(\ce{COCl}_{2}\)
    3. \(\ce{HF}\)
    4. \(\ce{SF}_{6}\)
    5. \(\ce{CS}_{2}\)
    6. \(\ce{SeF}_{4}\)
    7. \(\ce{AlCl}_{3}\)
    8. \(\ce{Cl}_{2}\ce{O}\)
    9. \(\ce{SiBr}_{4}\)
    10. \(\ce{N}_{2}\ce{O}\)

Lewis structures
  1. Draw the Lewis structures of the following polyatomic ions:
    1. \(\ce{SO}_{3}^{2-}\)
    2. \(\ce{PO}_{4}^{3-}\)
    3. \(\ce{NO}_{2}^{-}\)
    4. \(\ce{PF}_{4}^{+}\)
    5. \(\ce{AlCl}_{4}^{-}\)

Lewis structures
  1. Draw the Lewis structures for the following compounds:
    1. \(\ce{Cl}_{2}\)
    2. \(\ce{HI}\)
    3. \(\ce{PCl}_{3}\).

Lewis structures for chlorine, hydrogen iodide and phosphorus trichloride
  1. Determine the molecular formulas for the following compounds by identifying the values for the subscripts \(v,\,w,\,x\) and \(z\):
    1. \(\ce{H}_{x}\ce{S}\)

    \(x=2\)

    1. \(\ce{CCl}_{z}\)

    \(z=4\)

    1. \(\ce{PF}_{w}\)

    \(w=3\)

    1. \(\ce{HBr}_{v}\)

    \(v=1\)

  1. Draw the structural formulas for the following compounds:
    1. \(\ce{C}_{2}\ce{H}_{4}\)
    2. \(\ce{N}_{2}\)
    3. \(\ce{SO}_{3}\)
    4. \(\ce{HCN}\).

Structural formulas for methane, nitrogen gas, sulfur trioxide and hydrogen cyanide
  1. Use your understanding of coordinate covalent bonds to explain the formation of the following polyatomic ions:
    1. \(\ce{NH}_{4}^{+}\) from \(\ce{NH}_{3}\) and \(\ce{H}^{+}\)

    A coordinate covalent bond is formed between an empty orbital of one atom with a lone pair of another atom. In the ammonium ion (\(\ce{NH}_{4}^{+}\)), the nitrogen atom of ammonia donates a lone pair of electrons to the hydrogen cation, which has an empty \(1s\) orbital.

    1. \(\ce{H}_{3}\ce{O}^{+}\) from \(\ce{H}_{2}\ce{O}\) and \(\ce{H}^{+}\)

    A coordinate covalent bond is formed between an empty orbital of one atom with a lone pair of another atom. In a hydronium ion, the oxygen atom in the water molecule is donating one of their lone pairs to the hydrogen cation with a vacant \(1s\) orbital.

    1. \(\ce{BF}_{4}^{-}\) from \(\ce{BF}_{3}\) and \(\ce{F}^{-}\).

    A coordinate covalent bond is formed between an empty orbital of one atom with a lone pair of another atom. In \(\ce{BF}_{4}^{-}\) ion, the fluoride anion donates one of their lone pairs to an empty \(2p\) orbital of the boron atom of \(\ce{BF}_{3}\) which gives boron four covalent bonds.

  1. Predict the geometry of the following molecules:
    1. \(\ce{PF}_{3}\)

    Pyramidal

    1. \(\ce{SCl}_{2}\)

    Bent or angular

    1. \(\ce{SiBr}_{4}\).

    Tetrahedral

  1. Predict the geometry around each of the carbon atoms in \(\ce{C}_{2}\ce{Cl}_{2}\).

Structural formula for dichloroacetylene with its two carbon atoms labelled linear

  1. Predict the geometry of the following polyatomic ions:
    1. \(\ce{NH}_{2}^{-}\)

    Bent or angular

    1. \(\ce{CO}_{3}^{2–}\)

    Trigonal planar

    1. \(\ce{SO}_{4}^{2-}\).

    Tetrahedral

  1. The structure and 3D view of the amino acid aspartic acid is shown below.
    Structure and 3D view of aspartic acid

    Predict the geometry around the indicated carbon atoms.

Trigonal planar and tetrahedral
  1. Determine whether bonds formed between the following pairs of elements are ionic, polar covalent or non-polar covalent:
    1. \(\ce{S}\) and \(\ce{Cl}\)

    Polar covalent

    1. \(\ce{N}\) and \(\ce{H}\)

    Polar covalent

    1. \(\ce{C}\) and \(\ce{Br}\)

    Non-polar covalent

    1. \(\ce{Li}\) and \(\ce{F}\).

    Ionic

  1. Predict the polarity (polar or non-polar) of each of the following molecules:
    1. \(\ce{HCN}\)

    Polar

    1. \(\ce{NH}_{3}\)

    Polar

    1. \(\ce{CH}_{3}\ce{Br}\).

    Polar

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