Inorganic Chemistry - Atomic Structure Biology 2121 Chapter 2

Introduction (1). Cells are the basic units of living organisms Atoms ----- elements --- compounds (molecules) Matter (2). Elements 112 total (92 naturally occuring) 96% of body (C,O,H,N) 20 trace elements (3). Inorganic vs Organic Chemistry

Atomic Structure (1). What are atoms made of? (2). Properties Nucleus (protons and neutrons) Energy levels (electrons) (2). Properties Neutrons (0, 1 amu) Proton (+1, 1 amu) Electron (-1, 1/2000 amu) Marieb link

Elements and the Periodic Chart (1). Metals and Nonmetals (2). Atomic Number # of Protons in nucleus (3) Mass Number Protons + electrons Mass of a single atom!

Elements and the Periodic Chart

Average Atomic Mass and Isotopes What are isotopes? Same type of atoms with differing numbers of neutrons. Average of all isotopes Average atomic mass number Not all isotopes –equal amounts

Valance Electrons and Planetary Models Outer shell electrons Involved in bonding (2). Drawing Planetary Models of atoms Periodic chart (appendix C)

Valence Shells

Why are valence electrons important? Valence electrons are involved in bonding Electrons Transferred from one atom to another Shared between atoms