MAT E 273 Exam 1 QUESTIONS SOLVED 100%
Ionic Bond - Answers when atoms lose or gain electrons (strongest typed of bonding)
Covalent bonding - Answers electron sharing, close proximity due to orbital overlap, bonding is
directionally dependent
Metallic bonding - Answers electron "sea", valence electrons are donated to the bulk material and are
free to move throughout
Name the electronegativity ranges for bonding types - Answers x <= 0.4 nonpolar covalent
0.4<=x<=1.7 polar covalent
x>=1.7 ionic
Order from highest to lowest strength bonding types - Answers ionic
covalent
metallic
hydrogen
LDF
Keesom
Debye
LDF - Answers induced dipole - induced dipole attraction
What is responsible for bonding noble gases - Answers LDFs
What is the trend as atom size increases - Answers more opportunities for polarization along with an
increased magnitude of attractive dispersion forces
nonpolar molecule - Answers symmetric charge distribution on average over time, temporary
polarizations allow such molecules to bond
As n-alkanes increase carbon chain length what happens to LDFs? - Answers an increasing number of
them
Keesom forces - Answers Dipole - Dipole Attraction
Polar molecules variation in electronegativity - Answers varies by 0.5-2.0
Debye forces - Answers Dipole - Induced Dipole Attraction
, (between polar and nonpolar molecules)
Hydrogen bonding - Answers attraction between a permanently polarized molecule and adjacent atom
with a lone pair of electron on another molecule
(Only with H-N H-O H-N bonds)
What hybridization is graphite? - Answers sp2
What hybridization is diamond - Answers sp3
What other element(s) can feature sp3 hybridization? - Answers Si
Ge
Sn (at temps below 13.2 Celsius)
General trend of increasing bond strength, and increasing geometric requirements (low to high) -
Answers Metallic, Covalent, Ionic
Describe bonding in CH4 - Answers covalent bonding within the molecule, LDF bonding between
molecules
Covalent bonding - Answers directionally dependent, low ductility, low density
Three ways to determine Bonding - Answers 1. Electronegativity difference
2. % Ionic Character (good for non-metallic primary bonds that are mixed)
3. Ketelaar Triangle (for predominant bonds)
bonding contained in HF - Answers hydrogen bonding, also LDF between molecules
LDFs magnitude and number are affected by... - Answers magnitude is affected by the number of
electrons
number of LDFs is affected by the length of the carbon chain (for example)
Crystallography - Answers perfect, mathematically ideal structure
anisotropy - Answers material properties depend on orientation
Grain boundaries ___________ metals at low temperatures - Answers strenghten
Grain boundaries ___________ metal at high temperatures - Answers weaken
perfect single crystal - Answers long-range periodic arrangement of atoms, ions, or molecules described
entirely by a unit cell (rare in nature. difficult to make)
Ionic Bond - Answers when atoms lose or gain electrons (strongest typed of bonding)
Covalent bonding - Answers electron sharing, close proximity due to orbital overlap, bonding is
directionally dependent
Metallic bonding - Answers electron "sea", valence electrons are donated to the bulk material and are
free to move throughout
Name the electronegativity ranges for bonding types - Answers x <= 0.4 nonpolar covalent
0.4<=x<=1.7 polar covalent
x>=1.7 ionic
Order from highest to lowest strength bonding types - Answers ionic
covalent
metallic
hydrogen
LDF
Keesom
Debye
LDF - Answers induced dipole - induced dipole attraction
What is responsible for bonding noble gases - Answers LDFs
What is the trend as atom size increases - Answers more opportunities for polarization along with an
increased magnitude of attractive dispersion forces
nonpolar molecule - Answers symmetric charge distribution on average over time, temporary
polarizations allow such molecules to bond
As n-alkanes increase carbon chain length what happens to LDFs? - Answers an increasing number of
them
Keesom forces - Answers Dipole - Dipole Attraction
Polar molecules variation in electronegativity - Answers varies by 0.5-2.0
Debye forces - Answers Dipole - Induced Dipole Attraction
, (between polar and nonpolar molecules)
Hydrogen bonding - Answers attraction between a permanently polarized molecule and adjacent atom
with a lone pair of electron on another molecule
(Only with H-N H-O H-N bonds)
What hybridization is graphite? - Answers sp2
What hybridization is diamond - Answers sp3
What other element(s) can feature sp3 hybridization? - Answers Si
Ge
Sn (at temps below 13.2 Celsius)
General trend of increasing bond strength, and increasing geometric requirements (low to high) -
Answers Metallic, Covalent, Ionic
Describe bonding in CH4 - Answers covalent bonding within the molecule, LDF bonding between
molecules
Covalent bonding - Answers directionally dependent, low ductility, low density
Three ways to determine Bonding - Answers 1. Electronegativity difference
2. % Ionic Character (good for non-metallic primary bonds that are mixed)
3. Ketelaar Triangle (for predominant bonds)
bonding contained in HF - Answers hydrogen bonding, also LDF between molecules
LDFs magnitude and number are affected by... - Answers magnitude is affected by the number of
electrons
number of LDFs is affected by the length of the carbon chain (for example)
Crystallography - Answers perfect, mathematically ideal structure
anisotropy - Answers material properties depend on orientation
Grain boundaries ___________ metals at low temperatures - Answers strenghten
Grain boundaries ___________ metal at high temperatures - Answers weaken
perfect single crystal - Answers long-range periodic arrangement of atoms, ions, or molecules described
entirely by a unit cell (rare in nature. difficult to make)
