Pertemuan 1 Pertemuan 1 Jan 9, 2016
Pertemuan 1Pertemuan 1Jan 9, 2016
Atom sebagai partikel
Atom sebagai partikel dan gelombang
H. H.
H. H.
H H
IKATAN KOVALENIKATAN KOVALEN
Tumpang tindih orbital
Pembentukan Ikatan
Atom yang terpisah
atomsmovecloser
( Model tumpang tindih orbital)
OrbitalsOrbitals
The region of space around an atom in which an electron is likely to be found is an orbital.
The shape and size of the orbital are determined by a mathematical equation called a wave function.
OrbitalsOrbitals
When atoms combine to form molecules, they do so by combining the wave functions for the individual atomic orbitals.
We say that the orbitals “overlap.”The region of space defined by this
combination of orbitals is the molecular orbital.
Sigma BondsSigma BondsHead-on overlap of atomic
orbitalsElectron density is a symmetrical
cylinder around the bond axisAtomic orbital combinations that
give bonds:s s p p ps
Pi BondsPi BondsSide-on overlap of atomic orbitalsElectron density is above and below a
nodal plane on the internuclear axisAtomic orbital combinations that give
bonds:p p p d
HYBRIDIZATIONHYBRIDIZATION
HOW ARE THE OBSERVED BOND ANGLES ACHIEVED?
“Vision is the art of seeing things invisible.”Jonathan Swift
Xunhybridized atom
2s
2pz
2py
2px
2s
2pFORMATION OFFORMATION OFSPSP33 HYBRID ORBITALS HYBRID ORBITALS
Xsp3 hybridized atom
(1) (2) (3) (4)
FORMATION OFFORMATION OFSPSP33 HYBRID ORBITALS HYBRID ORBITALS
These orbital shapes arecartoons - actual shapesare shown on the nextslide. [animation]
Ikatan padaIkatan pada
Alkana sp3
Alkena sp2
Alkuna sp
C
Carbon has 4 valence electrons, 2s22p2
.. .
.
Carbon can form single, double or triple bonds
sp, sp2 and sp3 hybrid orbitals.
Let’s do sp3 first.
2p
2s
hybridize sp3
ALKANA
H
H
H
H
CC H
H
HH
H
H
C CH H
H
H H
H
POSTEST
Buatlah hibridisasi etana(Selengkaplengkapnya menurut pemahaman anda)Ditulis dalam kertasNama:NIM:
TUGAS KELOMPOKMenulis Hibridisasi yang mengandung unsur:
1.Kelompok 1 absen 1-6 unsur N2.Kelompok 2 absen 7-12 unsur O3.Kelompok 3 absen 8-18 unsur P4.Kelompok 4 absen 19-24 unsur Cl5.Kelompok 5 absen 25-32 unsur B6.Kelompok 6 absen 33-41 unsur F
Multiple Bonds and hybridization
Ethylene C CH
H
H
H
Each carbon is hybridized sp2 . The hydrogens are 1s. One of the double bonds is sp2 - sp2. The other one isp - p.
2p
2s
hybridize
2p
sp2
ALKENA
C C
Note that a double bond consists of a and a type bond
C CH
H
H
H
C CH
H
H
H
What about acetylene?
C CH HEach carbon atom is sp hybridized. The hydrogens areunhybridized, 1s orbitals.
2p
2s
hybridize
2p
sp
Note that a triple bond consists of a and 2 bonds. Thetwo bonds use unhybridized p orbitals.
ALKUNA
CCH H
C C HH
C
H
H HH
:
: ....
symmetrical moleculeall repulsions are equal
perfect tetrahedralall angles 109o28’
NH H: ....H
.. anglebecomeslarger
larger repulsion
repulsionsmaller angle becomes
smaller
not all pairs are equivalent
the unshared pairs repel morestrongly than the bonded pairs
Electron Pair RepulsionElectron Pair Repulsion
Effect of double bond and electronegativity
C CHH
H H
C OH
H
C CH2
H
H
C CH2
Cl
Cl
C CH2
F
FC O
F
F
C OCl
Cl
C OH
H117o
121.5o
121.5o
123o
125o
117o
114o
110o
116o
122o
116o
124.5o
126o
111o
108o
122o
OC
H
H
H
H
2s2p
sp3 hybrids
hybridization C OHH
H
Hsp3 sp3 Metanol
2s2p
sp2
hybridization
2p
2p
C OH
HC
HO
H
used forbond
used forbonds
sp2
sp2
C CCH
H
H
H
C C CH
H
H
Hallena
sp2sp2sp
CH
HH H
endview
molecule has a twist in the center
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