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Dipole moments
-What can you do with them?
add them up and they form a direction toward the more electronegative
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What can the poles do?
negative pole of one may react with the positive pole of anotehr
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In chemistry, what cannot you do?
break single bonds
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What do arrows indicate?
the flow of two electrons
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Sigma bonds are __
single bonds
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Pi bonds are __
sigma bond and another bond
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Where can't you push electrons to?
a saturated area
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In contrast to single bonds, what are double bonds?
shorter and stronger than single bonds
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Where should you put the negative charge?
on the most electronegative atom
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delocalization
- spreading out the charge--> stabilized
- lower in energy, much more readily accessed
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Explain formal charges in terms of neutral molecules.
if neutral, formal charges add up to zero
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For period 2 elements, what is the deal with charges?
no double charges exist
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Double charge rule
no double charges directly next to each other= too much repulsion
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Explain major and minor contributors.
In resonance, they both exist. The major will be the one that most likely occurs in nature
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When both resonance forms obey the octet rule, the major contributor is __
the one with the negative charge on the most electronegative atom
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Condensed structural formulas
- are written without showing all the individual bonds
- atoms bonded to the central atom are listed after hte central atom
- if there are two or more identical groups, parentheses and a subscript may be used to represent them
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Line angles are also called __
zig-zag structures
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At the end of every line and at the intersection of any lines in line-angle structures, there is __.
a carbon atom with four bonds. Hydrogen atoms are mentally supplied to fill the valency to four
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In line angle drawings, what must be shown.
atoms other than carbon and double and triple bonds
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Definitions of acids and bases
- arrhenius:
- - acid: forms H30+ in water
- - base: forms OH- in water
- Bronsted-Lowry:
- - acid: donates an H+
- - base: accepts an H+
- Lewis:
- - acid: accepts an electron pair to form a new bond
- - base: donates an electron pair to form a new bond
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Bronsted-Lowry acids are any species that __
donate a proton
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Bronsted-Lowry bases are any species that __
accept a proton
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conjugate acids and bases
- conjugate acid: when a base accepts a proton, it becomes an acid capable of returning that proton
- conjugate base: when an acid donates its proton, it becomes capable of accepting that proton back
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Effect of electronegativity on pKa
As the bond to H becomes more polarized, what?
H becomes more positive and the bond is easier to break
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Effect of size on pKa
As size increases, what?
- the H is more loosely held and the bond is easier to break
- a larger size also stabilizes an anion
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Lewis bases are
species with available electrons that can be donated to form a new bond
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Lewis acids are
species that can accept these electrons to form new bonds
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Since a Lewis acid accepts electrons, it is called an __
electrophile
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Nucleophile
donates electrons to a nucleus with an empty orbital (Lewis base)
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Electrophile
accepts a pair of electrons (same as Lewis acid)
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When forming a bond, __ attacks the __, so the arrow goes from __ to __.
- nucleophile
- electrophile
- -
- +
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When breaking a bond, the more __ receives the electrons.
electronegative atom
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