Chapter 2: The Chemistry of Life

Notes

Chapter 2 The Chemistry of Life I.​Atoms, Ions, and Molecules ​A.​The Chemical Elements 1.​ ​​2.​Elements are represented by one- or two-letter symbols ​​3.​24 elements play normal physiological roles in humans (Table 2.1, pg. 44) ​​​a.​6 elements (O, C, H, N, Ca, P) account for 98.5% body’s weight ​​​b.​6 elements (S, K, Na, Cl, Mg, Fe) account for 0.8% body’s weight ​​​c.​The remaining 12 elements are trace elements (Cr, Co, Cu, F, I, ​​​​​Mn, Mo, Si, Sn, V, Zn) ​​4.​Minerals- inorganic elements extracted from the soil by plants ​B.​Atomic Structure (Fig. 2.1, pg.44) ​​1.​Atom- ​​2.​The nucleus of an atom is composed of protons and neutrons ​​​a.​Protons (p+) have a single positive charge ​​​b.​Neutrons (no) have no charge ​​3.​Around the nucleus are one or more concentric clouds of electrons ​​​a.​Electrons (e-)- tiny particles with a single negative charge (Fig. 2.1) ​​​b.​Electrons determine the chemical properties of an atom ​​​c.​The number of electrons equals the number of protons ​​​d.​Electrons swarm the nucleus in electron shells (energy levels) and ​​​​​those of the outermost shell determine the bonding of an atom ​C.​Isotopes and Radioactivity ​​1.​Isotopes- elements...