Average Isotope Mass

• Same Element

• Different Mass Number

• WHICH MEANS DIFFERENT # of NEUTRONS

• Neutrons make atoms stable

• Unstable = Wants to fall apart

• Fall Apart = Split into smaller atoms

• Split Apart = RADIOACTIVE

What decay of Uranium - 238 looks like.

• DIFFERENT than Mass Number

• Average of all of the isotopes of an atom found in nature.

• % abundance of that isotope x actual mass of that isotope

• add together

• divide by 100 (if you didn't put into percentage first)

• CLOSEST TO ROUNDED AVERAGE ATOMIC MASS

• So the most abundant isotope of Gold would be?

• Gold - 197

• Ion means charged atom

• To be charged it needs more or less electrons than protons

• more electrons = NEGATIVE

• less electrons = POSITIVE

• Same as isotope

• includes charge in upper right

• + means LESS ELECTRONS than PROTONS

• (-) means MORE ELECTRONS than PROTONS