Humboldt State University ® Department of Chemistry

Richard A. Paselk
 

General Chemistry

Spring 2008
Exercise: Lewis Structures & VSEPR Theory

© R. Paselk 2008
 
 

Discussion Modules

 

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Lewis Structures, VSEPR Theory and Molecular Geometry

Draw Lewis Structures of the compounds below and when appropriate predict the shapes of molecules using VSEPR Theory. A Periodic Table is provided with Hi (red), Lo (gray) and Intermediate (green) Electronegativities indicated to aid in prediting ionic vs. covalent compounds.

Periodic Table of the Elements
   IA IIA IIIA IVA VA VIA VIIA VIIIA
   H  He
2 Li Be    B C N O F Ne
3 Na Mg IIIB IVB VB VI VIIB VIIIB IB IIB  Al Si P S Cl Ar
4 K Ca Sc  Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
5  Rb Sr  Y Zr Nb Mo Tc Ru Rh Pd  Ag  Cd  In Sn Sb Te I  Xe
6  Cs Ba Lu  Hf Ta  W Re Os Ir  Pt Au  Hg Tl  Pb Bi Po At Rn

  1. Phosphide ion

  2. Bromide ion

  3. Rubidium fluoride

  4. Cesium nitride

  5. Methane, CH4

  6. Hydrogen sulfide

  7. Carbon monoxide

    1. Does Carbon monoxide have polar bonds?

    2. Is it a polar molecule? Explain.

  8. Barium iodide

  9. Ammonia, NH3

    1. Does Ammonia have polar bonds?

    2. Is it a polar molecule? Explain.

Set A - Answers 1-9

Periodic Table of the Elements
   IA IIA IIIA IVA VA VIA VIIA VIIIA
   H  He
2 Li Be    B C N O F Ne
3 Na Mg IIIB IVB VB VI VIIB VIIIB IB IIB  Al Si P S Cl Ar
4 K Ca Sc  Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
5  Rb Sr  Y Zr Nb Mo Tc Ru Rh Pd  Ag  Cd  In Sn Sb Te I  Xe
6  Cs Ba Lu  Hf Ta  W Re Os Ir  Pt Au  Hg Tl  Pb Bi Po At Rn

  1. Formaldehyde, CH2O

    1. Does formaldehyde have polar bonds?

    2. Is it a polar molecule? Explain.

  2. Strontium nitride

  3. Cyanide ion, CN-

  4. Carbon dioxide, CO2

    1. Does carbon dioxide have polar bonds?

    2. Is it a polar molecule? Explain.

  5. Chloromethane, CH3Cl

  6. Acetic acid, CH3CO2H

  7. Ozone, O3

  8. Sulfite ion

    1. Does Sulfite ion have polar bonds?

    2. Is it a polar molecule? Explain.

  9. Water, H2O

    1. Does Water have polar bonds?

    2. Is it a polar molecule? Explain.

  10. Carbocation, CH3+

Set B - Answers 1-10

Periodic Table of the Elements
   IA IIA IIIA IVA VA VIA VIIA VIIIA
   H  He
2 Li Be    B C N O F Ne
3 Na Mg IIIB IVB VB VI VIIB VIIIB IB IIB  Al Si P S Cl Ar
4 K Ca Sc  Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
5  Rb Sr  Y Zr Nb Mo Tc Ru Rh Pd  Ag  Cd  In Sn Sb Te I  Xe
6  Cs Ba Lu  Hf Ta  W Re Os Ir  Pt Au  Hg Tl  Pb Bi Po At Rn

1. Determine the Geometry of Phosphorus pentachloride, PCl5.

  1. Does Phosphorus pentachloride have polar bonds?

  2. Is it a polar molecule? Explain.

2. Determine the Geometry of Sulfur tetrafluoride, SF4.

  1. Does Sulfur tetrafluoride have polar bonds?

  2. Is it a polar molecule? Explain.

3. Determine the Geometry of Chlorine trifluoride, ClF3.

4. Determine the Geometry of Triiodide ion, I3-.

5. Determine the Geometry of Arsenic hexafluoride ion, AsF6-.

6. Determine the Geometry of Iodine pentachloride, ICl5.

  1. Does Iodine pentachloride have polar bonds?

  2. Is it a polar molecule? Explain.

7. Determine the Geometry of Xenon tetrafluoride, XeF4.

Is Xenon tetrafluoride a polar molecule? Explain.

Set C - Answers 1-7

In addition to these exercises you should familiarize yourself with the text materials referenced below.

Go to Report to get credit for Module

© R A Paselk

Last modified 1 April March 2008