If you have not already done so, download Avogadro for free and watch the tutorials if necessary.
Write in your notebook the structural formulas of the following compounds using the Lewis electron dot.
- Aluminum oxide (IUPAC nomenclature or in Italian)
- Perchloric anhydride
- Carbonic acid
- Nitrous acid
Then import the structures of the same compounds on Avogadro (sequence File → import → fetch by chemical name) and check that you have written them correctly, verifying the bond angles, and therefore the VSEPR structures in properties.