1. What is the charge of an electron?
2. How many electrons can occupy the first energy level of an atom?
3. What is the mass number of an atom equal to?
4. What is an ion?
5. What is the relative mass of a proton?
6. What are isotopes?
7. Who proposed the nuclear model of the atom?
8. What is the charge of a neutron?
9. What happens when an electron absorbs electromagnetic radiation?
10. What determines which element an atom is?