Practice Quiz

1. Aluminum _____ Zinc _____ Bromine _____ Sodium _____ Flourine _____ Gold _____ Copper _____ Nickel _____ 9. Ca __________ 10. C __________ Mg __________ Hg __________ Zn __________ Cl __________ K __________ Sn __________ Practice Quiz

2. Atomic Number Protons Electrons (for now) Atomic Mass Protons + Neutrons 9 F 19.0 • Neutrons = atomic mass – atomic number • Periods/Energy levels are rows that go across • Families/Groups columns that go up & down • Electrons in outer energy level – same as column

3. How Atoms Differ • Periodic Table • Ordered by the number of protons • the only thing about an atom that doesn’t change! • If you change proton number you change the element

6. Mass of Individual Atom • Mass of proton or neutron = 1.67 x 10-24 g • Mass of electron = 9.08 x 10-28 g or 1/1840 the mass of proton • Atomic Mass = weighted average of the isotopes of an element

7. How to calculate Atomic Mass • The same as calculating your grade

8. Let’s Practice • Calculate the atomic mass 107Ag 106.905 amu 52% 109Ag 108.905 amu 48%

9. Let’s Practice 2. Calculate the atomic mass 1H 12% 2H 48% 3H 40%

10. Let’s Practice 3. Boron has two naturally occurring isotopes, boron-10 (abundance 19.8%, mass 10.013 amu) boron-11 (abundance 80.2%, mass=11.009 amu) Calculate the average atomic mass

11. Let’s Practice 4. Calculate the average atomic mass 12C 12.0014 amu 87.3% 14 C 13.9960 amu 12.7%

12. Let’s Practice • Calculate the average atomic mass Iron-55 67.8% Iron-58 32.2%

13. Let’s Practice 6. Calculate the atomic mass Helium has two naturally occurring isotopes, helium-3 and helium-4. The average abundance of helium-3 is 27.2%, and the average abundance of helium-4 is 72.8%