Chem 100 Exam 3 Practice Problems
1. Draw Lewis dot symbols for the following elements: Mg and O.
2. Show an equation representing the first ionization energy of sodium (i.e. formation of a
sodium ion using its Lewis dot symbol).
3. Using Lewis dot symbols, show the formation of a binary ionic compound between Al and
O. Is the formula the same using the “criss-cross” rule?
4. What kind of bond forms between 2 F atoms? Show it. Why can’t the other type of bond
form?
5. Give Lewis structures for the following showing all steps (including counting the number of
electrons used). Verify with the 6N + 2 rule. Show all resonance structures where
applicable: NCl3, CO3-2, CaCO3.
6. Draw a resonance “hybrid” of CO3-2.
7. Put the following in order of increasing polar bonds: Be-F, B-H, C-N.
The electronegativities are as follows: Be=1.5, B=2.0, F=4.0, H=2.1, C=2.5, N=3.0.
8. Write the balanced equation when C3H8O undergoes combustion.
9. Write the balanced equation when NaCl undergoes decomposition into its elements in
their most stable form.
10. Write the equation when sulfuric acid dissociates in water.
11. Given Table 7-2, write the molecular reactions that take place (if any) for: a) Sn + AgNO3
b) Ag + HClO4
12. Given Table 7-3, write the net ionic reactions that take place for: a) AgNO3 + MgCl2
b) KCl + Na2SO4
13. Given Table 7-3, predict which of the following would be a solid precipitate:
PbSO4, AgI, (NH4)2SO4, MgO, NaC2H3O2.
14. Write total ionic equations for: a) HClO4 + LiOH
b) HCl + NaOH