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Unformatted text preview: The Chemical Nature of Life
• Like the abiotic world, living organisms are a collection of atoms (representing different elements) that are linked by chemical bonds to form molecules. • Unique to life, are the myriad of molecules primarily comprised of one or more of these four elements: carbon, hydrogen hydrogen, oxygen & nitrogen % of
atomic – comprise 96% of body weight element number body wt. – 4%: Ca, K, S, Na, P, Mg, Cl – Trace elements (0.01%): I, Fe, Co, Zn, B, Mn, Se, Human • Emergent properties: atoms → molecules, example: 2H + O2 → H2O; properties of elements O, H vs. that of water. Atomic Structure ATOMS 101
HAVE SUBATOMIC PARTICLES a. d.
combine to get g.
located in determine located in: b. atomic number
constant for each e.
may differ in various h. shells
outer shell called c. f. isotopes i. Atomic Structure
The element helium
atomic number electrons: (–) charge; # electrons = # protons nucleus of: protons: (+) charge & neutrons (uncharged) atomic mass • Isotopes of an atom: different number of neutrons (proton & electron quantity identical)
– all exhibit same chemical p...
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This note was uploaded on 10/16/2010 for the course HE 012928 taught by Professor Storrs,london during the Spring '10 term at École Normale Supérieure.
- Spring '10