SI WORKSHEET 17
1. Give the Lewis structure, resonance structure, formal charge, and both electron and
molecular geometries for nitrogen dioxide, NO2. Where are the positive and negative
charges located in this molecule?
N:5 – (1+3)= +1 Positive charge is on nitrogen
O1:6 – (6 +1)=-1 Negative charge on oxygen
O2:6- (4+2)= 0
EG: Trigonal planar
MG: Angular/bent
2. Give the Lewis structure for CO2. Does it have any resonance structures? What are the
molecular and electron geometries for carbon dioxide
carbon dioxide does have other resonance structures but they are not good
resonance structures so they are not drawn.
EG: Linear
MG:Linear
3. Give the structure of CHFClBr. Which bond in this molecule would be the strongest
bond? Which bond is most polar? Least polar? What are the electron and molecular
geometries?
The C—F bond is the strongest and most polar, the C—Br bond is the least polar. The
electron and molecular geometries are both tetrahedral.
4. Which bond is strongest? HF, HCl, HBr, or HI? What kind of bond is between each of
these atoms (nonpolar covalent, polar covalent, or ionic)? HF is the strongest bond
because 1. The nuclei of both atoms are closer together because they are smaller atoms
2. There is a bigger electronegativity difference and this difference lies in the ionic bond
range while the other bonds are polar covalent ( HCl and HBr) or nonpolar covalent (HI)
5. What molecule has the stronger bond, HCN or CO? Which molecule has the shortest
bond between two atoms? CO has the stronger bond and the shorter bond, the shorter
the bond, the stronger it is.
6. N2 + 3 H2  2 NH3. ΔH= 92 kJ What is the enthalpy based on bonds? What are the
electron and molecular geometries for ammonia? Electron geometry of ammonia is
tetrahedral and the molecular geometry is trigonal pyramidal
7. What is the electron and molecular geometry for perchlorate ion? How many valence
electrons? The electron and molecular geometry is equal if there is not a lone pair on
the central atom. Here they are equal and so they are equal to a tetrahedral
configuration. Perchlorate ion has 32 valence electrons
8. What is the electron and molecular geometry for sulfate? Same thing as above. 32
valence electrons and no lone pairs on central atom (sulfur) and so the geometries are
both of tetrahedral configuration