7. Three Rules for Filling Electrons into subenergy level (leave third rule blank)
8a. Define valence electrons and explain how you can determine number of valence electrons of an element
8b. Why is it important to know where valence electrons are located in an atom?
9. Write electron configuration and number of electrons for:
b. Zinc (does not have valence electrons)
10. How many neutrons, electrons and protons (and show how you write it in symbols) in the isotopes:
11. Define atomic mass and calculate the atomic mass of sulfur (use the table I gave you):