Please take your own notes. Atomic Math Please take your own notes.

# of Protons Atomic number = number of protons 7

# of Electrons Atomic number = number of electrons 7 Note: This is true for ATOMS where the positives (protons) balance out the negatives (electrons). This is NOT true for IONS which have extra charges…

Atomic Mass Atomic mass = # Protons + # Neutrons 7 Definition: Nucleon is a particle in the nucleus. Protons and neutrons are both “nucleons” Note: Atomic mass = # of nucleons

Number of Neutrons Atomic mass = # Protons + # Neutrons # Neutrons = Atomic Mass - Atomic Number 7

Na Different Notations Atomic Mass is always the larger number Outside of the periodic table, you might see something like this: Atomic Mass 23 Na 11 Atomic number Atomic Mass is always the larger number

Where do electrons go? 1st Shell Holds up to 2 2nd Shell Holds up to 8 3rd Shell Holds up to 18 Rule: Fill from the inside out