CHEM 101 Chapter 2: Chem Module 2 Chapter 2
15 Sep 2015
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Module 2 (2. 1-2. 7): atoms molecules and ions (textbook notes) 2. 1: atomic structure- protons, electrons, and neutrons: protons have + charge; electrons have charge; neutrons have neutral charge, chemical properties of elements depend on electrons. 2. 2: atomic number and mass: all elements have the same number of protons and electrons, carbon 12 standard (notated as z) neutrons / carbon=12u. : 1u=(1/12th) mass of carbon with 6 protons and 6: atomic mass. : atoms with same atomic number and different atomic mass. Ex: hydrogen has the isotopes protium (mass=1), deuterium (mass=2), tritium (mass=3) Percent abundance= (number of atoms of a given isotope/total number of all isotopes) x 100. : average mass of an atom in the natural sample of the element. Atomic weight = [(percent abundance of isotope 1 / 100) x mass of isotope 1] + [(percent abundance of isotope 2 / 100) x mass of isotope 2] + .
