elements are one kind of atom
elements chemically bonded together to form an atom
mass of 1 and 1 positive charge
mass 1 and no charge
mass taken as 0 and 1 negative charge
protons and neurons form thr nucleon, electrons circle the nucleon
the amount of protons in an atom form the atomic number
the first shell has the lowest energy level -the further the shell the higher the energy level -the first shell can only hold 2 electrons -the second and third shells can hold 8 electrons
-period number tells you how many electron shells are occupied -the group number tells you the amount of outer electrons
-atoms of the same element with the same number of protons but different number of neutrons
the nucleon number goes over the electron number
carbon-12 is the standard for atomic mass units alll masses are relative to the carbon 12
(atomic mass of the first isotopes* % abundance) + (atomic mass of the second isotope* % abundance)