What is hybridization? Please watch this video to know more..
VIDEO
THEORY
QUIZ
HC
methane ethylene
CH
acetylene
What can you see from these 3 compounds??
All of the three compound is covalently bonded with each other
Carbon in methane is bonded with four hydrogen atoms and has single bond
Each carbon in ethane is bonded with three other groups and the carbon is connected by the double bond
Carbon in acetylene is bonded with only two groups and the carbon is connected by the triple bond
We can see that the central atom, which is carbon is covalently bonded with other groups in the compound. But, how does the bonding occur??
Valence Bond Theory
Lets take a closer look towards these two theory
Hybrid Orbital Theory
Valence bond theory describes covalent bonding as the overlap of two atomic orbitals with the electron pair in the resulting bond being shared by both atom. From this theory, carbon can only form two bonds because on its valence shell only has two unpaired electron and the resulting molecule is CH2.
Carbon : 1s 2s 2p
-CH2 is a very reactive molecule and cannot exist outside the molecular system -So, how does the bonding occur??? -now, lets take a look at the hybrid orbital theory
hybrid orbital
New orbital that results from the combination of two or more atomic orbitals
According to the hybrid orbital theory, an electron form 2s orbital is excited to the 2p orbital Now, the carbon is in the excited state The bonding of molecule now is called hybridisation Hybridisation is the combination of two or more atomic orbitals to form the same number of atomic orbitals
Carbonground state : 1s 2s 2p
Carbonexcited state : 2s 2p
So now, we can proceed to the next part on how are we going to determine type of hybridisation
How To Determine Type Of Hybrid Orbital?
HC
methane ethylene
CH
acetylene
Back to the structure that we see at the beginning The obvious differences between the three molecule is the type of bonding that they have where methane has single bond, ethylene double bond and acetylene triple bond The type off bonding will determine their type of hybridisation.
METHANE, CH3
Now, lets take a look again at the carbon in excited state Since carbon is bonded to four hydrogen atom, four hybrid orbitals is used The hybridization now is called as the sp3 hybrid orbitals
Carbonexcited state : 2s Carbonhybridized : sp3 sp3 sp3 sp3 2p
WHY SP3 HYBRID ORBITALS?
Because it is formed from 1 s orbital and 3 p orbitals forming the sp3 hybrid orbitals Mixing the spherical 2s orbital and three dumbbell shaped 2p orbital produces four orbital having large lobe and small lobe
s orbital
p orbital
sp3 hybrid orbital
hydrogen atom overlaps with the four sp3 hybridized orbital form four sigma bond
The geometry is tetrahedral
The bond angle is 109.5o
ETHYLENE, C2H4
We can see that carbon molecule in ethylene is bonded to three groups only which is carbon and two hydrogen This means that, only three hybrid orbitals is used Thus, forming the sp2 hybridization
Carbonexcited state : 2s 2p
Carbonhybridized : sp2 sp2 sp2
2p
But now, what will happen to the 2p orbital that is unhybridized?
oThe second C-C bond result from the side-by-side overlaps oSide by side overlaps create electron density above and below plane of sp2 hybrid orbitals. oThis bond is called bond. o bonds are weaker and easily broken than sigma bond
How many bonds present in the ethylene molecule?
Sigma bonds
Sigma bonds
What is the geometry of this compound?
There are six bonds in the ethylene molecule 1 sigma bond within C-C and 4 sigma bonds between C-H 1 pi bond between C-C molecule
Pi bond
The geometry of ethylene molecule is trigonal planar The hybrid orbitals all lie on the same plane It cannot rotate freely because of the presence of pi bond H-C-H and H-C-C bond angles are about 120o
HC
ACETYLENE, C2H2
CH
By looking at the Lewis structure of acetylene, can we describe the molecular geometry, and the type of hybridization??
Yes, we can Based on the Lewis structure, each Carbon atom is singly bonded to the Hydrogen atom and triply bonded to each Carbon atom. So, each carbon atom is surrounded by two groups resulting linear geometry and sp hybridized. The bond angle is 180o
Carbonexcited state : 2s Carbonhybridized : sp sp 2p
2p 2p
Since there are only two groups surrounding the carbon atom, only 2 hybrid orbitals is used to form the sp hybrid orbitals which are the C-H bond and C-C bond The other two 2p orbital is unhybridised
What is the difference between hybridized orbital and unhybridised orbital??
Hybridized orbital is the C-H bond and the C-C bond. Both bonds result from the end-to-end overlap of sp hybrid orbital and 1s orbital and also sp hybrid orbital with sp hybrid orbital on each carbon This result the formation of sigma bond Unhybridized orbital results from the side-by-side overlap between the two sp orbital to the other carbons creating the 2nd and 3rd bond of the C-C triple bond. Both of these bonds are pi bonds
The linear geometry of the acetylene molecule
How many sigma and pi bond are present? There are three sigma bonds in acetylene which are the C-C bond and two from the C-H bond. Meanwhile, there are 4 pi bonds in these compound
QUIZ
CHOOSE THE RIGHT ANSWER FOR THE QUESTION.
1. Which molecule is not linear?
A. BeF2
B. BeH2
C. CO2
D. H20
CLICK TO SHOW EXPLANATION
2. Which molecule is linear?
A. NO2
B. ClO2
C. CO2
D. H2S
CLICK TO SHOW EXPLANATION
3. Which of the following molecule has 120o bond angle?
A. IF3
B. PCl3
C. HCl
D. C2H4
CLICK TO SHOW EXPLANATION
4. Which of the following hybrid orbitals consist of a pi bond and sigma bond I. II. III. IV. A. I and II C2H6 BeH2 CO2 C2H4 B. I, II, and III
C. II, III and IV
D. I, II, III and IV
CLICK TO SHOW EXPLANATION
5. The central atom in a CH4 molecule is in hybrid state. The shape of molecule will be
A. Trigonal pyramidal
B. Tetrahedral
C. Pyramidal
D. Trigonal Planar
CLICK TO SHOW EXPLANATION
CONGRATULATIONS, THAT IS THE CORRECT ANSWER!!
SORRY, PLEASE TRY AGAIN..
1. ANSWER : D
H2O did not have linear shape because oxygen atom have two lone pair electrons
The lone pair repels the two Hydrogen atom, to bond angle of 104.5o
CONGRATULATIONS, THAT IS THE CORRECT ANSWER!!
SORRY, PLEASE TRY AGAIN..
2. ANSWER : C
the carbon in CO2 is sp hybridized.
All sp hybridized is linear
CONGRATULATIONS, THAT IS THE CORRECT ANSWER!!
SORRY, PLEASE TRY AGAIN..
3. ANSWER : D
C2H4 is sp2 hybrid orbitals
Thus, shape is trigonal planar
The bond angle is 120o
CONGRATULATIONS, THAT IS THE CORRECT ANSWER!!
SORRY, PLEASE TRY AGAIN..
4. ANSWER : C II,III, IV
Structure I, C2H6 did not have any pi bond
It undergo sp3 hybridization
CONGRATULATIONS, THAT IS THE CORRECT ANSWER!!
SORRY, PLEASE TRY AGAIN..
5. ANSWER : B
Geometry of CH4 is tetrahedral
Carbon is bonded to four hydrogen atom forming sp3 hybrid orbital
Geometry of sp3 hybrid orbital is tetrahedral
ACTIVITY 2 ACTIVITY 3 ACTIVITY 1
ACTIVITY 4
Instruction to play this game. Roll a dice. Move the button according to the number on the dice. When you reach the ladder, you can simply move up the ladder. But, if you reach the snake, you must choose any number from 1 until 15 and answer the question. When it is answered correctly, then the game can be continued.
QUESTIONS
CLICK TO CHECK THE ANSWER
CLICK TO CHECK THE ANSWER
Use the hybridization theory to explain the formation of the following molecules, regarding to Lewis structure Ground state Hybridized state a) O2 b) ClO3c) OF2 d) CH3+
CLICK TO CHECK THE ANSWER
Deduce the type of hybridization of each atom, draw the overlap of the orbitals, and state the bond angles for the following compounds.
CH3Cl NO 3 CH3C CCH2OH
G P M P L A N A R H U Z X C F C
B O H J E O I D N U I C A U J V
D Y Y J W L I H M Y K V Q I T T
S U N O I T A Z I D I R B Y H E
N D F N S Q Y C K E J N S Z Y T
X V E D S S F K E W W M G V M R
Z A Z I T G S T L T E U H M E A L
R X G T R H
T M A H U H K
A V D U C Y J A B F Z G E G A D
A B L A T I B R O F X N L N N R
A S K M U D E E N G C I P H E A
N W T F R A R Q D I B S O P R L
K Q W S E K E W S K V C F H W B
F R Q A P O E N Q L V V R F A L
L E C E T H Y L E N E Z E I S R
Lets find the hidden word.. acetylene bond ethylene hybridization Lewis structure linear methane orbital pi planar sigma single tetrahedral
D D Q Y E F B T H
S R S Z L K D H E
CLICK TO CHECK THE ANSWER
G P M P L A N A
B O H J E O I D
D Y Y J W L I H
S U N O I T A S
N D F N S Q Y C
X V E D S S F K
Z A Z I T G S T L
R X G T R H
T M A H U H K
A V D U C Y J A
A B L A T I B R
A S K M U D E E
N W T F R A R Q
K Q W S E K E W
F R Q A P O E N
L E C E T H Y L
R
H U
N
U I C A U J V
M
Y K V Q I T T
I
D I R B Y H E
K
E J N S Z Y T
E
W W M G V M R
L
T E U H M E A Y
D
Q
R
S Z
B
F Z G E G A D
O
F X N L N N R
N
G C I P H E A
D
I B S O P R L
S
K V C F H W B
Q
L V V R F A L
E
N E Z E I S R
Finally, I got all the answers.. (^_~)
Z X C F C
E F B T H
L K D H E
LIST THE DIFFERENCES OF HYBRID ORBITLAS BETWEEN METHANE, ETHYLENE AND ACETYLENE
HYBRIDIZATION
SP3 HYBRID ORBITALS
SP2 HYBRID ORBITALS
SP HYBRID ORBITALS
STRUCTURE
GEOMETRY BOND ANGLE
TETRAHEDRAL 109.5o
TRIGONAL PLANAR 120o
LINEAR 180o
BONDING GROUP
NON-BONDING GROUP SIGMA BOND FORM PI BOND FORM
4 BONDING GROUP
0 NON-BONDING GROUP 4 SIGMA BOND 0 PI BOND
3 BONDING GROUP
1 NON-BONDING GROUP 3 SIGMA BOND FOR EACH CARBON 1 PI BOND
2 BONDING GROUP
2 NON-BONDING GROUP 2 SIGMA BOND FOR EACH CARBON 2 PI BOND
There are three types of hybridisation which is sp3, sp2 and sp hybrid orbitals
From our learning session today, we can conclude that
Geometry for sp3 hybridization is tetrahedral and the bond angle is 109.5o
Geometry for sp hybridization is linear and bond angle is 180o
Geometry of sp2 hybridization is trigonal planar and the bond angle is 120o
THE END
