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WHY DO DIFFERENT COMPOUNDS HAVE DIFFERENT PROPERTIES????
PROPERTIES IONIC COMPOUNDS
MOLECULAR COMPOUNDS
state at room temp solid mainly gases, some liquids and soft solids
melting point high low
solubility in water most are soluble most are insoluble
conducts electricity when in solution
yes no
Sep 78:54 AM
Chemical BondingLearning Goals:
To review the difference in electron activity between an Ionic bond and a Covalent bond
To define electronegativity, and understand its importance in covalent bonds
To distinguish between a nonpolar and a polar covalent bond
Jan 149:02 AM
Bonding involves the interaction of VALENCE ELECTRONS of atoms
The new compound formed is more stable than the atoms were separately
*movie of rxn
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One atom loses its valence electrons and the other atom gains themGenerally between a metal atom (low ionization energy) and a nonmetal atom (high electron affinity)
Metal loses valence electrons…..becomes a positive ion (+)
Nonmetal gains valence electrons….becomes a negative ion ()
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Drawing Lewis Structures for Ionic Compounds
ArNe
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Two atoms share valence electrons
Generally between 2 nonmetals (high ionization energy, electron affinity)
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Drawing Lewis Structures for Covalent Compounds
NeNe.. ......
. . ......
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lewis structure movie
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Sometimes the shared pair of electrons is NOT SHARED
EQUALLY!!!
AND THIS AFFECTS THE PROPERTIES OF THE COVALENT COMPOUND
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NONPOLAR (PURE) COVALENT BOND: BOTH ARE RELATIVELY JUST AS GOOD AT ATTRACTING THOSE VALENCE ELECTRONS
POLAR COVALENT BOND: ONE ATOM IS A LITTLE BETTER AT ATTRACTING THE ELECTRONS INTO ITS VALENCE SHELL THAN THE OTHER
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ELECTRONEGATIVITY increases because smaller atoms have a stronger positive nuclear charge, and can draw electrons closer to it.
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ELECTRONEGATIVITY HAS TO DO WITH
HOW WELL AN ATOM HOLDS
THE SHARED PAIR OF ELECTRONS
IN ITS SHELL
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When two atoms are involved in a bond, COMPARE THEIR ELECTRONEGATIVITIES.The difference between their ELECTRONEGATIVITIES will determine the type of bond.
How do we use ELECTRONEGATIVITY?
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electronegativity movie
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September 10, 2013
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OXYGEN GAS, O2
=
EN O =
EN O =
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WATER, H2O
=
"dipole"
EN H =EN O =
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Drawing Lewis Structures for Polar Covalent Compounds
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Lewis movie
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September 10, 2013
Jan 149:05 AM