Practice Quiz 1.Aluminum _____ 2.Zinc_____ 3.Bromine_____ 4.Sodium_____ 5.Flourine_____ 6.Gold_____ 7.Copper_____ 8.Nickel _____ 9. Ca __________ 10. C__________ 11.Mg__________ 12.Hg__________ 13. Zn__________ 14. Cl__________ 15. K__________ 16. Sn__________

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

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

Mass of Individual Atom Mass of proton or neutron = 1.67 x g Mass of electron = 9.08 x g or 1/1840 the mass of proton Atomic Mass = weighted average of the isotopes of an element

How to calculate Atomic Mass The same as calculating your grade % of your grade Your average Calculations Homework 10%88 Quiz/Test 30%80 Final 60%72

Let’s Practice 1.Calculate the atomic mass 107 Ag amu52% 109 Ag amu48%

Let’s Practice 2. Calculate the atomic mass 1 H12% 2 H48% 3 H40%

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

Let’s Practice 4. Calculate the average atomic mass 12 C amu87.3% 14 C amu12.7%

Let’s Practice 5.Calculate the average atomic mass Iron % Iron %

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%