1. Chapter 11B Notes Determining Isotope Masses

2. Intro What is the mass of an atom with 6 protons and 6 neutrons? 12 What is the mass of an atom with 6 protons and 7 neutrons? 13 Notice how carbon doesn’t just have a mass of 12 but 12.011, hence neutrons can change.

3. What is an Isotope A when the amount of neutrons change in an atom so the overall atomic mass changes.

4. How to determine the Atomic Mass from percent abundance The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for a mass of 62.93amu and 30.8% for a mass of 64.93amu. Calculate the average atomic mass of copper. 0.692X62.93+0.308X64.93=63.546