1 Unit 2: BIOMOLECULES, Part 1 INORGANIC CHEMISTRY Atomic structure and the periodic table Bonds – ionic, covalent (and hydrogen) Solubility and polarity, electrolytic properties Properties of water, hydrogen bonding Acids, bases and buffers
Dec 30, 2015
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Unit 2: BIOMOLECULES, Part 1
INORGANIC CHEMISTRY
Atomic structure and the periodic table Bonds – ionic, covalent (and hydrogen) Solubility and polarity, electrolytic properties Properties of water, hydrogen bonding Acids, bases and buffers
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Atomic structure
Atomic number Atomic mass
Number of electrons Electron energy levels # valence electrons
Number of protons Number of protons +
number of neutrons (isotopes vary in #
neutrons)
Equal to # of protons Row on periodic table Group # (1-8) (active bonding
electrons)
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Bonds involve valence electrons
Metals tend to transfer electrons
Nonmetals tend to take electrons when bonding with metals
Nonmetals tend to share electrons when bonding to other non-metals
Ions: charged atoms due to the gain or loss of electrons
Ionic bonds: cations and anions
Covalent bonds: shared electrons
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Covalent and Ionic bonds
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Ionic bonds
Metals form cations when they lose valence electrons
Nonmetals form anions when they gain valence electrons
Generally are hydrophilic, dissolve in water, form electrolytes
Ionic equations show the ions into which they separate
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Covalent bonds
Shared electrons Non-metals to non-metals Do not form ions in solution May be polar or non-polar
covalent Covalent bonds are stronger
than ionic bonds CHNOPS compounds of
living things (“organic”) are covalently bonded
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H2O is a polar molecule, covalently bonded but with an unequal distribution of shared electrons
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Water is the “versatile solvent”
The hydrogen bondsbetween hydrogen and oxygen cause unique properties ofwater
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Polar solvents dissolve polar solutes
Sugar dissolves in water
Salt dissolves in water
Only ionic compounds form electrolytes in water
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Nonpolar solutes do not dissolve in polar solvents (water)
Salad oil
Oil
Gasoline
Vegetable shortening
butter
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Acids, Bases, Buffers
Acids release H+ in solution
Bases release OH- in solution
Buffers resist changes in pH
pHyrion paper
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pH scale
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Biological systems depend on buffers
Narrow tolerances to changes in pH
Acid rain alters pH of soils and aquatic ecosystems
Limestone is used as a buffer in acidified lakes