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Everything is made up of matter
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Only 25 elements are essential for life
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Matter is made up of atoms
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96% of living matter is N,H,C,O
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Atoms consist of protons, Neutrons, and Electrons
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4% of living matter is Ca,K,S,P
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Electron Effects-
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determine chemical behavior of atom
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depends on the # of the electrons in the outermost shell called the "valance electrons" & "Valance shell"
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atoms want a complete octate (8 valance electrons) except for hydrogen (wants 4)
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Atoms tend to complete a partially filled valance shell or empty a partially filled valance shell.
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This drives reactions & completes bonds
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Strong Bonds
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Weak Bonds
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Covalent Bond -> share electrons evenly
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Hydrogen Bond -> attraction between + and -
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Ionic
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Why are covalent bonds so strong?
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Multiple covalent bonds
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* 2 atoms share a pair of electrons
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* Double Bonds ex: O2
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* both atoms are holding on
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* 2 Pairs of electrons
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* Very stable
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* Triple bonds ex: N2 (very strong)
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* Forms Molecules ex: H2O
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* 3 pairs of electrons
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Polar Covalent
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Non-Polar Covalent
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No areas of + or - because electrons are shared evenly
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Electrons are shared unequally by atoms
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Ex: Hydrocarbons (Methane CH4)
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Ex: (H2O) -> O is more - and pulls electrons away from the H making O have a - charge.
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Balanced and stable
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Attraction between +H in one H2O molecule and the -O in another H2O molecule
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Weak Bond
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
