1. Reading the Periodic Table

2. The top number is the atomic number or the number of ______________________ Cl is an abbreviation for ______________________ The bottom number can be displayed two different ways : The top image displays 35.453 or the ___________ (the weighted average mass of the mixture of isotopes of an element) protons the element name (chlorine) atomic mass

3. This bottom image displays 35 or the _______________ Which equals the _______ + ________ in the nucleus Chlorine has how many protons _____ Chlorine has how many electrons _____ 35 mass number protons neutrons 17

4. On the periodic table elements are neutral therefore positive charges equal the negative charges To determine the number of neutrons subtract protons from the mass number Chlorine has how many neutrons ____ 35 18

5. Rules Atomic Number = # of ________ # of Protons = # of _________ (when atom is neutral) Mass Number = Protons + ________ or ________ = Mass Number – Protons protons Electrons Neutrons

6. Practice ElementAtomic ## Protons# ElectronsMass ## Neutrons Lithium Carbon Hydrogen Silver 333 7 4 666126 11110 47 108 61