Inorganic Chemistry - Atomic Structure Biology 2121 Chapter 2 Biology 2121 Chapter 2

Introduction (1). Cells are the basic units of living organisms – Atoms  elements ---  compounds (molecules) – Matter (2). Elements – 116 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? – 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 – Protons (3) Mass Number – Protons + electrons – Mass of the 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 (1). Valance electrons – 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