Chemical Bonding Flashcards
Hypovalent elements
Be, B, Al
Hypervalent elements
(More than octet)
P S Cl
As Se Br
VSEPR Theory made by
Nylholm and Gillespie
Order of bond pairs / lone pairs
LP—LP > BP—LP > BP—BP
most least
If outer atoms are more EN, bond angle will
Decrease
Linear sp (180º) examples
BeCl2, CO2, HgCl2, CS2, NO2+
Bent angular (120º) sp2 examples
SO2, NO2, O3, SnCl2, GeCl2
Bent/ V-shape (104-109º) sp3 examples
H2O, H2S, H2Se, H2Te
F2O, Cl2O, Br2O, I2O
Trigonal planar
AB3 120º sp2
Trigonal planar examples
AlCl3, BrF3, SO3, CH3+, CO3 2-, NO3-
Trigonal pyramidal
AB3 (107-109º) sp3
Trigonal pyramidal examples
NH3, PH3, AsH3, SbH3, BiH3, H3O+
Tetrahedral
AB4 (109º) sp3
Tetrahedral examples
CH4, SiH4, PbH4, CCl4, SiCl4, GeCl4, SO4 -2, PO4 -3
AB5 AB6 AB7 AB8
AB5 = Trigonal bipyramidal (e.g. PCl5)
AB6 = Square planar bipyramidal (e.g. SF6, SeCl6)
AB7 = Pentagonal bipyramidal (e.g. IF7)
AB8 = Hexagonal bipyramidal
s—s bond has
p—p bond has
s—s bond has free rotation
p—p bond has limited rotation
bonds strength order
s—s > s—p > p—p
Saturated hydrocarbons are ___ hybridized
sp3
C=C bond length
1.34 Aº
Unsaturated hydrocarbons are ___ hybridized
sp2
As s character increases EN ______
Increases
C—C bond length
1.54 Aº
Bond length _______ across the period and up the group
Decreases
Bond length proportional to
1/EN
Benzene bond lengths
1.39 Aº
Cation size _____ across the group
Anion size ______ across the group
Cation decreases
Anion decreases (but anions are bigger than cations)
Covalent radii =
Bond length / 2
Highest bond energy molecule
HF
1 mol of H2 has how much ∆H
436 kJ/mol
BE is proportional to
EN
BE order
C (triplebond) O > C=O > C—O
1Aº = ____ cm / _____ m
10^-8 cm
10^-10 m
1D = _______ esu cm
1D = ________ SI Unit
10^18 esu cm
3.34 x 10^-30 Cm (SI unit)
Symmetrical = Polar/Non-polar
Assymetrical Polar/Non-polar
Symmetrical = Non-polar
Assymetrical = Polar
Order of reactivity of polar etc
Ionic > Polar > Non-polar
Non-polar geometries
Trigonal planar and CH4 and CCl4
Primary amines more or less polar than ammonia
Primary amines are more polar
Cis alkene = Polar/Non-polar
Trans alkene = Polar/Non-polar
Cis = Polar
Trans = Non-polar
Ionic character % =
(µobserved / µionic) x 100
Ionic = directional or non directional
Non directional
(ioNic = NoN)