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ionic crystals are held together by
the attraction of positive ions and negative ions
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what forces hold the atoms in molecules together?
- intramolecular forces
- (not electrically charged ions)
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polarity
- Different EN's, so there isn't equal sharing of shared pairs
- The highest EN attracts the shared pair more strongly and causes that end to have a partial negative charge.
- The other end is partial pos, causiong a polar molecule
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In most cases, polar covalent bonds produce what kind of molecules?
Polar molecules
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A polar molecule is often called a
dipole/dipole moment
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What does a high dipole moment mean?
the intramolecular forces in a molecule are strong, resulting in a higher MP and BP
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Can polar covalent bonds be present in a nonpolar molecule? Why?
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Weak forces
intermolecular forces (between 2 molecules) and act to hold 2 or more molecules together
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van der Waals forces
the attraction of an electron from 1 atom and the proton froma second atom
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dipole-dipole forces
occur when 2 molecules that normally are dipoles attract
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dipole-induced dipole forces
occur when a dipole attracts a nonpolar molecule by inducing this molecule to form a temporary dipole
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dispersion or London forces
occur when 2 nonpolar molecu;es attract because of the random movement of their electrons
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molecules held by weak forces tend to be
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ligands are what kind of molecules/have what charges?
- polar molecules- no charge
- or negative ions
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complex ion
when ligands cluster around the central positive ion
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coordination number
number of points of attachment
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Most common coordination number
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coordination 4
- square planar
- Ni, Pd, Pt, CO
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coordination 2
- always linear
- formed with positive ions
- Ag, Au, Hg
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didentate
- ligand attaches to the central positive atom at 2 spots
- oxalato
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molecular ligands are always
- polar
- have at least one unshared pair
- ammonia
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which names change to latin?
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coordination compound
- form when complex ions are involved in the formation of a compound.
- 3 ways
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1st way to form coordination compound
the charge of the positive ion is equal to the total charges of the ligands
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2nd way to form a coordination compound
neither the atom nor the ligands have a charge
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3rd and most common way to form a coordination compound
complex ions form a compound with 1 or more monoatomic, polyatomic, or complex ion of the opposite charge
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