CEM 141 Exam 3
- ANS-Draw CH4
- ANS-Sigma bond
- Metal + nonmetal
- Element with low electronagitivity + element with high electronegativity.
- Metals form cations, non-metals form anions. - ANS-What is an ionic compound?
- Positively charged ions.
- Formed from metals losing electrons.
- Small than corresponding atoms.
- Usually corresponds to loss of electrons back to "core"
-Highly charged ions form stronger bonds-which are more stable. - ANS-What are cations
- Present in POLAR substances.
- Typically stronger than LDF's
- HCl, CH3F, CH2O, CH3OCH3 - ANS-What are Dipole-dipole interactions?
-A single bond is always a sigma bond
-All the rest are always pi bonds
-Sigma bonds allow for rotation around the bond
-Pi bonds do not (it would break the pi bond) - ANS-Things to remember about VSEPR...
-C - sp hybridized
-One sigma bond
-Two pi bonds
-High electron density between atoms. - ANS-Triple Bonds
-Energy released when an ionic lattice forms ions in the gas phase.
-Na+(g) + Cl-(g)=NaCl(s) - ANS-What is Lattice Energy?
-Forms four bonds.
-Can bond with C,H,O,N,S,P
-Properties of these compounds are emergent. - ANS-Why is carbon so important?
-Hydrocarbons with one or more carbon-carbon double bonds.
-One sigma bond, one pi bond.
- Restricted rotation around the double bond.
-C is sp2 hybridized. - ANS-Alkenes
, -Increases across a row (noble gasses are exceptions)
-Decreases down a period
-Directly correlated to effective nuclear charge. - ANS-Electronegativity trends
-Negatively charged ions
- Non-metals gaining electrons.
- Larger than corresponding atom.
- Charge usually corresponds to gain of electrons to next filled shell (noble gas configuration) -
ANS-What are anions?
-sp
-linear
-180 - ANS-2 centers of electron density
-sp2
-trigonal planar
-120 - ANS-3 centers of electron density
-sp3
-tetrahedral
-109.5 - ANS-4 centers of electron density
-sp3d
-trigonal bipyramidal
-90, 120 - ANS-5 centers of electron density
-sp3d2
-octahedral
-90 - ANS-6 centers of electron density
-Temporary fluctuating dipoles
-Depends on size, surface area, and shape of the molecule.
- Only interaction present in non-polar molecules.
- Present in ALL substances (between molecules) - ANS-What are London Dispersion Forces?
-tetrahedral
-4 centers of electron density - ANS-What is the electron pair geometry around water?
-The idea that covalent bonds are formed when orbitals of different atoms overlap -
ANS-Valence Bond Theory
-Valence electrons of one atom attracted to nucleus of other atom
-Electrons are located between nuclei
-Bond formation lowers the PE of the system and stabilizes the system. - ANS-Covalent Bonds
- ANS-Draw CH4
- ANS-Sigma bond
- Metal + nonmetal
- Element with low electronagitivity + element with high electronegativity.
- Metals form cations, non-metals form anions. - ANS-What is an ionic compound?
- Positively charged ions.
- Formed from metals losing electrons.
- Small than corresponding atoms.
- Usually corresponds to loss of electrons back to "core"
-Highly charged ions form stronger bonds-which are more stable. - ANS-What are cations
- Present in POLAR substances.
- Typically stronger than LDF's
- HCl, CH3F, CH2O, CH3OCH3 - ANS-What are Dipole-dipole interactions?
-A single bond is always a sigma bond
-All the rest are always pi bonds
-Sigma bonds allow for rotation around the bond
-Pi bonds do not (it would break the pi bond) - ANS-Things to remember about VSEPR...
-C - sp hybridized
-One sigma bond
-Two pi bonds
-High electron density between atoms. - ANS-Triple Bonds
-Energy released when an ionic lattice forms ions in the gas phase.
-Na+(g) + Cl-(g)=NaCl(s) - ANS-What is Lattice Energy?
-Forms four bonds.
-Can bond with C,H,O,N,S,P
-Properties of these compounds are emergent. - ANS-Why is carbon so important?
-Hydrocarbons with one or more carbon-carbon double bonds.
-One sigma bond, one pi bond.
- Restricted rotation around the double bond.
-C is sp2 hybridized. - ANS-Alkenes
, -Increases across a row (noble gasses are exceptions)
-Decreases down a period
-Directly correlated to effective nuclear charge. - ANS-Electronegativity trends
-Negatively charged ions
- Non-metals gaining electrons.
- Larger than corresponding atom.
- Charge usually corresponds to gain of electrons to next filled shell (noble gas configuration) -
ANS-What are anions?
-sp
-linear
-180 - ANS-2 centers of electron density
-sp2
-trigonal planar
-120 - ANS-3 centers of electron density
-sp3
-tetrahedral
-109.5 - ANS-4 centers of electron density
-sp3d
-trigonal bipyramidal
-90, 120 - ANS-5 centers of electron density
-sp3d2
-octahedral
-90 - ANS-6 centers of electron density
-Temporary fluctuating dipoles
-Depends on size, surface area, and shape of the molecule.
- Only interaction present in non-polar molecules.
- Present in ALL substances (between molecules) - ANS-What are London Dispersion Forces?
-tetrahedral
-4 centers of electron density - ANS-What is the electron pair geometry around water?
-The idea that covalent bonds are formed when orbitals of different atoms overlap -
ANS-Valence Bond Theory
-Valence electrons of one atom attracted to nucleus of other atom
-Electrons are located between nuclei
-Bond formation lowers the PE of the system and stabilizes the system. - ANS-Covalent Bonds
