Chemistry SM-1131 Week 5 Lesson 1. Dr. Jesse Reich Assistant Professor of Chemistry Massachusetts Maritime Academy Fall 2008. Class Today. Test Wednesday Poem Movie Review: Periodic Table, Isotopes and Atomic Mass Atomic Mass Review for the test. Quote.
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Dr. Jesse Reich
Assistant Professor of Chemistry
Massachusetts Maritime Academy
Just be careful because change will hurt.
Hydrogen is the element
1 is the atomic number
1.0079 is the atomic mass
Groups/families are up and down
Rows/periods are left to right
Group 1. Alkali Metals
Group 2. Alkaline Earth Metals
Group 3-12 Transition Metals
Group 17. Halogens
Group 18. Noble Gases
Main group 1,2 13-18
H, C, N, O, P, S, Se are organic elements
B, Si, Ge, As, Sb, Te, Po are metaloids
It’s an average mass of all the different isotopes.
(%abundance * mass) + (%abundance*mass) etc… = atomic mass
20.00*.9038 + 21.00*.0027 + 22.00*.0925 = 20.1677 = 20.17 amu = atomic mass
So the masses on the periodic tables are average masses of all the isotopes