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11.E: Exercises

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    357333
    • Anonymous
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    11.2:  Representing Valence Electrons with Dots

    1. Is it necessary for the first dot around an atomic symbol to go on a particular side of the atomic symbol?
    Answer

    No. The first dot can go on any side of the atomic symbol.

     

    1. What column of the periodic table has Lewis electron dot diagrams with two electrons?
    Answer

    IIA or 2

     

    1. What column of the periodic table has Lewis electron dot diagrams that have six electrons in them?
    Answer

    VIA or 16

     

    1. Draw the Lewis electron dot diagram for each element.
      1. strontium
      2. silicon
    Answer
    1. \(⋅\,\mathrm{Sr}\,⋅\)
    2.  \(\overset⬝{\underset⬝{⋅\,\mathrm{Si}\,⋅}}\)

     

    1. Draw the Lewis electron dot diagram for each element.
      1. krypton
      2. sulfur
    Answer
    1. \(\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{Kr}:}}\)
    2. \(\overset⬝{\underset{⬝\,⬝}{:\mathrm{S}\,⋅}}\)

     

    1. Draw the Lewis electron dot diagram for each element.
      1. potassium
      2. phosphorus
    Answer
    1. \(\mathrm K\,⋅\)
    2. \(\overset⬝{\underset⬝{:\mathrm{P}\,⋅}}\)

     

    1. Draw the Lewis electron dot diagram for each element.
      1. bromine
      2. gallium
    Answer
    1. \(\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{Br}\,⋅}}\)
    2. \(\overset⬝{\underset⬝{\mathrm{Ga}}}\,⋅\)

     

    11.3:  Ionic Bonds

    1. How many electrons does a Ba atom have to lose to have a complete octet in its valence shell?
    Answer

    2

     

    1. How many electrons does a Pb atom have to lose to have a complete octet in its valence shell?
    Answer

    4

     

    1. How many electrons does an Se atom have to gain to have a complete octet in its valence shell?
    Answer

    2

     

    1. How many electrons does an N atom have to gain to have a complete octet in its valence shell?
    Answer

    3

     

    1. Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: P, I, Mg, Cl, In, Cs, O, Pb, Co?
    Answer

    P, I, Cl, and O would form anions because they are nonmetals. Mg, In, Cs, Pb, and Co would form cations because they are metals.

     

    1. Which of the following atoms would be expected to form negative ions in binary ionic compounds and which would be expected to form positive ions: Br, Ca, Na, N, F, Al, Sn, S, Cd?
    Answer

    Br, N, F, and S would form anions because they are nonmetals. Ca, Na, Al, Sn, and Cd would form cations because they are metals.

     

    1. Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds:
      1. P
      2. Mg
      3. Al
      4. O
      5. Cl
      6. Cs
    Answer
    1. P3-
    2. Mg2+
    3. Al3+
    4. O2-
    5. Cl-
    6. Cs+

     

    1. Predict the charge on the monatomic ions formed from the following atoms in binary ionic compounds:
      1. I
      2. Sr
      3. K
      4. N
      5. S
      6. Li
    Answer
    1. I-
    2. Sr2+
    3. K+
    4. N3-
    5. S2-
    6. Li+

     

    1. Name two ions with the same Lewis electron dot diagram as the Cl ion.
    Answer

    S2- and P3-

     

    1. Draw the Lewis electron dot diagram for each ion.
      1. Mg2+
      2. S2−
    Answer
    1. Mg2+ (no electrons)
    2. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{S}:}}\right]^{2-}\)

     

    1. Draw the Lewis electron dot diagram for each ion.
      1. H+
      2. Br
    Answer
    1. H+ (no electrons)
    2. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{Br}:}}\right]^-\)

     

    1. Draw the Lewis electron dot diagram for each ion.
      1. Al3+
      2. N3−
    Answer
    1. Al3+ (no electrons)
    2. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{N}:}}\right]^{3-}\)

     

    1. Write the Lewis symbols for each of the following ions:
      1. As3
      2. I
      3. Be2+
      4. O2–
      5. Ga3+
      6. Li+
      7. N3–
    Answer
    1. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{As}:}}\right]^{3-}\)
    2. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{I}:}}\right]^-\)
    3. Be2+ (no electrons)
    4. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{O}:}}\right]^{2-}\)
    5. Ga3+ (no electrons)
    6. Li+ (no electrons)
    7. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{N}:}}\right]^{3-}\)

     

    1. Many monatomic ions are found in seawater, including the ions formed from the following list of elements. Write the Lewis symbols for the monatomic ions formed from the following elements:
      1. Cl
      2. Na
      3. Mg
      4. Ca
      5. K
      6. Br
      7. Sr
      8. F
    Answer
    1. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{Cl}:}}\right]^-\)
    2. Na+ (no electrons)
    3. Mg2+ (no electrons)
    4. Ca2+ (no electrons)
    5. K+ (no electrons)
    6. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{Br}:}}\right]^-\)
    7. Sr2+ (no electrons)
    8. \(\left[\overset{⬝\,⬝}{\underset{⬝\,⬝}{:\mathrm{F}:}}\right]^-\)

     

    11.4:  Covalent Bonds

    1. How many electrons will be in the valence shell of H atoms when it makes a covalent bond?
    Answer

    2

     

    1. How many electrons will be in the valence shell of non-H atoms when they make covalent bonds?
    Answer

    8

     

    1. What is the Lewis electron dot diagram of I2
    Answer

    I2 Lewis structure.JPG

     

    1. What is the Lewis electron dot diagram of H2S? 
    Answer

    H2S Lewis structure.JPG

     

    1. What is the Lewis electron dot diagram of NCl3?
    Answer

    NH3 Lewis structure.JPG

     

    1. What is the Lewis electron dot diagram of SiF4
    Answer

    SiH4 Lewis structure.JPG

     

    11.6:  Writing Lewis Structures for Molecular Compounds

    1. Draw the Lewis structure for each substance.
      1. SF2
      2. C2Cl2 (assume two central atoms)
    Answer
    1. SF2 Lewis structure.JPG
    2. C2Cl2 Lewis structure.JPG

     

    1. Draw the Lewis structure for each substance.
      1. PI3
      2. CS2
    Answer
    1. PI3 Lewis structure.JPG
    2. CS2 Lewis structure.JPG

     

    1. Draw the Lewis structure for each substance.
      1. GeH4
      2. ClF
    Answer
    1. GeH4 Lewis structure.JPG
    2. ClF Lewis structure.JPG

     

    1. Draw the Lewis structure for each substance.
      1. AsF3
      2. POCl
    Answer
    1. AsF3 Lewis structure.JPG
    2. POCl Lewis structure.JPG

     

    1. Draw the Lewis structure for each substance. Double or triple bonds may be needed.
      1. SiO2
      2. C2H4 (assume two central atoms)
    Answer
    1. SiO2 Lewis structure.JPG
    2. C2H4 Lewis structure.JPG

     

    1. Write the Lewis structure for the diatomic molecule P2, an unstable form of phosphorus found in high-temperature phosphorus vapor.
    Answer

    P2 Lewis structure.JPG

     

    1. Write Lewis structures for the following:
      1. H2
      2. HBr
      3. PCl3
      4. HNNH
      5. H2CNH
    Answer
    1. H2 Lewis structure.JPG
    2. HBr Lewis structure.JPG
    3. PCl3 Lewis structure.JPG
    4. HNNH Lewis structure.JPG
    5. CH2NH Lewis structure.JPG

     

    1. Write Lewis structures for the following:
      1. O2
      2. H2CO
      3. ClNO
      4. SiCl4
      5. ClCN
    Answer
    1. O2 Lewis structure.JPG
    2. H2CO Lewis structure.JPG
    3. ClNO Lewis structure.JPG
    4. SiCl4 Lewis structure.JPG
    5. ClCN Lewis structure.JPG

     

    1. Carbon tetrachloride was formerly used in fire extinguishers for electrical fires. It is no longer used for this purpose because of the formation of the toxic gas phosgene, Cl2CO. Write the Lewis structures for carbon tetrachloride and phosgene.
    Answer

    CCl4CCl4 Lewis structure.JPGCl2CO:  Cl2CO Lewis structure.JPG

     

    1. The arrangement of atoms in several biologically important molecules is given here. Complete the Lewis structures of these molecules by adding multiple bonds and lone pairs. Do not add any more atoms.
      1. the amino acid serine:  A Lewis structure is shown. A nitrogen atom is single bonded to two hydrogen atoms and a carbon atom. The carbon atom is single bonded to a hydrogen atom and two other carbon atoms. One of these carbon atoms is single bonded to two hydrogen atoms and an oxygen atom. The oxygen atom is bonded to a hydrogen atom. The other carbon atom is single bonded to two oxygen atoms, one of which is bonded to a hydrogen atom.
      2. urea:  A Lewis structure is shown. A nitrogen atom is single bonded to two hydrogen atoms and a carbon atom. The carbon atom is single bonded to an oxygen atom and another nitrogen atom. That nitrogen atom is then single bonded to two hydrogen atoms.
      3. pyruvic acid:  A Lewis structure is shown. A carbon atom is single bonded to three hydrogen atoms and another carbon atom. The second carbon atom is single bonded to an oxygen atom and a third carbon atom. This carbon is then single bonded to two oxygen atoms, one of which is single bonded to a hydrogen atom.
      4. uracil:  A Lewis hexagonal ring structure is shown. From the top of the ring (moving clockwise), three carbon atoms, one nitrogen atom, a carbon atom, and a nitrogen atom are single bonded to each another. The top carbon atom is single bonded to an oxygen atom. The second and third carbons and the nitrogen atom are each single bonded to a hydrogen atom. The next carbon atom is single bonded to an oxygen atom, and the last nitrogen atom is single bonded to a hydrogen atom.
      5. carbonic acid:  A Lewis structure is shown. A carbon atom is single bonded to three oxygen atoms. Two of those oxygen atoms are each single bonded to a hydrogen atom.

     

    Answer
    1. A Lewis structure is shown. A nitrogen atom is single bonded to two hydrogen atoms and a carbon atom. The carbon atom is single bonded to a hydrogen atom and two other carbon atoms. One of these carbon atoms is single bonded to two hydrogen atoms and an oxygen atom. The oxygen atom is bonded to a hydrogen atom. The other carbon is single bonded to two oxygen atoms, one of which is bonded to a hydrogen atom. The oxygen atoms have two lone pairs of electron dots, and the nitrogen atom has one lone pair of electron dots.
    2. A Lewis structure is shown. A nitrogen atom is single bonded to two hydrogen atoms and a carbon atom. The carbon atom is single bonded to an oxygen atom and one nitrogen atom. That nitrogen atom is then single bonded to two hydrogen atoms. The oxygen atom has two lone pairs of electron dots, and the nitrogen atoms have one lone pair of electron dots each.
    3. A Lewis structure is shown. A carbon atom is single bonded to three hydrogen atoms and a carbon atom. The carbon atom is single bonded to an oxygen atom and a third carbon atom. This carbon is then single bonded to two oxygen atoms, one of which is single bonded to a hydrogen atom. Each oxygen atom has two lone pairs of electron dots.
    4. A Lewis hexagonal ring structure is shown. From the top of the ring, three carbon atoms, one nitrogen atom, a carbon atom and a nitrogen atom are single bonded to one another. The top carbon is single bonded to an oxygen, the second and third carbons and the nitrogen atom are each single bonded to a hydrogen atom. The next carbon is single bonded to an oxygen atom and the last nitrogen is single bonded to a hydrogen atom. The oxygen atoms have two lone pairs of electron dots, and the nitrogen atoms have one lone pair of electron dots.
    5. A Lewis structure is shown. A carbon atom is single bonded to three oxygen atoms. Two of those oxygen atoms are each single bonded to a hydrogen atom. Each oxygen atom has two lone pairs of electron dots.

     

    11.7:  Predicting the Shapes of Molecules

    1. What is the basic premise behind VSEPR?
    Answer

    Electrons groups (bonds and lone pair electrons) want to be as far from each other as possible due to the negative charges in the groups repelling each other.

     

    1. What is the difference between the electron group geometry and the molecular geometry?
    Answer

    Electron group geometry tells where all electron groups are located. Molecular geometry tells where the atoms are located.

     

    1. Identify whether the following molecules are linear or bent.
      1. H2S
      2. HCN
      3. CS2
    Answer
    1. bent 
    2. linear
    3. linear

     

    1. Identify whether the following molecules are linear or bent around the central atoms.
      1. C2Cl2 (both C atoms are central atoms and are bonded to each other)
      2. N2H2 (both N atoms are central atoms and are bonded to each other)
    Answer
    1. linear
    2. bent

     

    Contributions & Attributions

     


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