ch 1: structure and bonding
DESCRIPTION
CH 1: Structure and Bonding. Renee Y. Becker CHM 2210 Valencia Community College. Organic Chemistry (present definition): the chemistry of carbon compounds Organic Chemistry (Historical definition): - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/1.jpg)
1
CH 1: Structure and Bonding
Renee Y. Becker
CHM 2210
Valencia Community College
![Page 2: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/2.jpg)
2
Organic Chemistry (present definition): – the chemistry of carbon compounds
Organic Chemistry (Historical definition): – Study of compounds extracted from living organisms,
study of compounds having the vital force
Vitalism: – The belief that natural products needed a “vital force” to
create them– In the 19th century experiments showed that organic
compounds could be synthesized from inorganic compounds
![Page 3: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/3.jpg)
3
Friedrich Wohler
• In 1828, Wohler synthesized urea from ammonium cyanate
heatNH4
+ OCN
- H2N C NH2
O
ureaAmmonium cyanate (inorganic)
![Page 4: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/4.jpg)
4
Natural Product or Synthesized
• Plant-derived compounds and synthesized compounds are identical (almost)
– You can tell them apart by 14C dating
– Synthesized compounds have a lower content of radioactive 14C, their 14C has decayed over time
– BUT, plant-derived compounds are recently synthesized from CO2 in the air and therefore have a higher content of radioactive 14C
![Page 5: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/5.jpg)
5
• Not all carbon compounds are organic
– Diamonds, graphite, CO2, NH4+ -OCN, Na2CO3
• Derived from minerals and have inorganic properties
– Most of the millions of carbon compounds are classified as organic
![Page 6: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/6.jpg)
6
Structure of the Atom
![Page 7: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/7.jpg)
7
Atomic Orbitals
![Page 8: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/8.jpg)
8
![Page 9: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/9.jpg)
9
• Aufbau principle: Place electrons in lowest energy orbital first.
• Hund’s rule: Equal energy orbitals are half-filled, then filled.
Electronic Configurations
![Page 10: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/10.jpg)
10
![Page 11: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/11.jpg)
11
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 7s 7p
Increasing Energy
[He][Ne] [Ar] [Kr] [Xe] [Rn]
Core
![Page 12: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/12.jpg)
12
Example 1: Electron Configuration
Draw electron configuration
1. Cl
2. Cl-
3. Mg
4. Mg2+
5. Fe3+
![Page 13: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/13.jpg)
13
• Ionic bonding: electrons are transferred.
• Covalent bonding: electron pair is shared.
Bond Formation
![Page 14: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/14.jpg)
14
Lewis Structures
• Bonding electrons
• Nonbonding electrons or lone pairs
Satisfy the octet rule!
C
H
H
H
OH
![Page 15: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/15.jpg)
15
![Page 16: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/16.jpg)
16
Multiple Bonding
![Page 17: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/17.jpg)
17
Example 2: Lewis Dot Structures
Draw Lewis structures for the following
a) NH3
b) CH3CH2F
c) CH3OCH3
d) BF3
e) C3H4
![Page 18: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/18.jpg)
18
Calculating Formal Charge
C
H
H
H
C
O
O P
O
OO
O
3-
Formal charge =
(# own valence electrons in free atom)-(# own valence electrons in bonded atom)
Put in formal charges
![Page 19: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/19.jpg)
19
Ionic Structures
C
H
H
H N
H
H
H
+
Cl-
Na O CH3 or O CH3Na+
_X
![Page 20: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/20.jpg)
20
Example 3: Lewis Dot Structures
Draw the Lewis structure for the following compounds or ions, showing formal charges
a) (CH3)+
b) (CH3)-
c) NH4Cl
d) H3O+
e) (CH3)2NH2Cl
![Page 21: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/21.jpg)
21
Valence Bond Theory
1. Covalent bonds are formed by overlapping of atomic orbitals, each of which contains one electron of opposite spin.
2. Each of the bonded atoms maintains its own atomic orbitals, but the electron pair in the overlapping orbitals is shared by both atoms.
3. The greater the amount of orbital overlap, the stronger the bond.
![Page 22: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/22.jpg)
22
Valence Bond Theory
• Linus Pauling: Wave functions from s orbitals & p orbitals could be combined to form hybrid atomic orbitals.
![Page 23: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/23.jpg)
23
• sp hybrid: acetylene HH
Bond angle 180Electron pair Geometry linear
![Page 24: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/24.jpg)
24
• sp2 hybrid: EthyleneH
H
H
H
Bond angle 120 (varies)Electron pair Geometry Trigonal Planar
![Page 25: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/25.jpg)
25
• sp2 hybrid (π bond):
![Page 26: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/26.jpg)
26
• sp3 hybrid: Ethane H
H
H
H
H
H
Bond angle 109.5 (varies)Electron pair Geometry Tetrahedral
![Page 27: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/27.jpg)
27
sp3d hybrid:
![Page 28: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/28.jpg)
28
• sp3d2 hybrid:
![Page 29: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/29.jpg)
29
Example 4: Hybridization
What is the hybridization of the non-hydrogen atoms?
H
HH
H
H
H
H
H
OH
HH
H
HH
HH
O
OHH
HH
H
H
HH
1.
2.
3.
4.
![Page 30: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/30.jpg)
30
Molecular Orbital Theory
• The molecular orbital (MO) model provides a better explanation of chemical and physical properties than the valence bond (VB) model.
– Atomic Orbital: Probability of finding the electron within a given region of space in an atom.
– Molecular Orbital: Probability of finding the electron within a given region of space in a molecule.
![Page 31: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/31.jpg)
31
Molecular Orbital Theory
• Additive combination of orbitals () is lower in energy than two isolated 1s orbitals and is called a bonding molecular orbital.
![Page 32: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/32.jpg)
32
Molecular Orbital Theory
• Subtractive combination of orbitals () is higher in energy than two isolated 1s orbitals and is called an antibonding molecular orbital.
![Page 33: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/33.jpg)
33
Molecular Orbital Theory
• Molecular Orbital Diagram for H2:
![Page 34: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/34.jpg)
34
Molecular Orbital Theory
• Molecular Orbital Diagrams for H2– and
He2:
![Page 35: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/35.jpg)
35
Chemical Formulas
Full structural formula (no lone pairs shown)
Line-angle formula
Skeletal
Condensed structural formula
Molecular formula
Empirical formula
CH3COOH
C2H4O2
CH2O
C
H
H
H
C
O
O H
OH
O
![Page 36: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/36.jpg)
36
![Page 37: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/37.jpg)
37
![Page 38: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/38.jpg)
38
Example 5: Chemical Formulas
Draw the condensed structural formula for the following
OH
O1. 2.
3. 4.
![Page 39: CH 1: Structure and Bonding](https://reader036.vdocuments.mx/reader036/viewer/2022062309/56813a2e550346895da21723/html5/thumbnails/39.jpg)
39
Example 6: Chemical Formulas
Draw the skeletal structure
1. CH3(CH2)4CH3
2. CH3CH(CH3)2
3. CH3CH(CH3)CH(CH2CH3)CH2CH3
4. C(CH3)4