1. A common model-building kit has a scale of 2 cm to the angstrom unit. What magnification factor would this be over the actual atomic sizes? Roughly how big would atoms be in these models? If nuclei were shown, how big would they be on the same scale?

2. Which are heavier, neutrons or electrons? Which are more highly charged? What counterbalances the charge on the protons in a neutral atom? Where is the proton charge located in the atom, and where is the counterbalancing charge?

3. What is the difference between the nuclei of hydrogen and helium atoms? How does this affect the number of electrons in each atom?

4. What is the difference between the various kinds of hydrogen atoms? What are such variations in the same type of atom called?

5. If you know that an atom is a carbon atom, what can you tell about the number of electrons, neutrons, and protons? What new information do you have if you know that it is carbon-13?