See for past JEE questions from this chapter
http://iit-jee-chemistry-ps.blogspot.com/2007/12/past-jee-questions-ch5.html
See for some application questions
http://iit-jee-chemistry-ps.blogspot.com/2007/12/application-questions-ch-5-bonding.html
JEE Syllabus
Orbital overlap and covalent bond;
Hybridisation involving s, p and d orbitals only;
Orbital energy diagrams for homonuclear diatomic species;
Hydrogen bond;
Polarity in molecules, dipole moment (qualitative aspects only);
VSEPR model and shapes of molecules (linear, angular, triangular, square planar, pyramidal, square pyramidal, trigonal bipyramidal, tetrahedral and octahedral).
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Main Topics in TMH JEE Book
COVALENT BOND
COORDINATE BOND
IONIC BOND
QUANTUM MECHANICAL EXPLANATION OF COVALENT BOND
HYBRIDIZATION
VALENCE SHELL ELECTRON-PAIR-REPULSION MODEL
HYDROGEN BOND
RESONANCE
MOLECULAR ORBITAL METHOD
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JEE syllabus and sections of Jauhar's Book (Class XI)
Orbital overlap and covalent bond; 6.5, 6.6, 6.7, 6.15, 6.18
Hybridisation involving s, p and d orbitals only; 6.18 (d orbitals not described)
Orbital energy diagrams for homonuclear diatomic species;
Hydrogen bond; 6.20
Polarity in molecules, dipole moment (qualitative aspects only); 6.14
VSEPR model and shapes of molecules (linear, angular, triangular, square planar, pyramidal, square pyramidal, trigonal bipyramidal, tetrahedral and octahedral). 6.13 and 6.13
Section of Jauhar Chapter 6
1. Cause of chemical combination
2. Lewis symbols
3. Octetl rule andmodes of chemical combination
4. Ionic or electrovalent bond
5. Covalent bond
General properties of covalent bonds
7. Co-ordinate covalent bond
8. Formation of ionic bond
9. Lattice enthalpy of ionic crystals
10. Born-haber Cycle for lattice enthalpies
11. General properties of ionic compounds
12. Geometry of shapes of molecules
13. Valence Shell Electron Pair Repulsion (VSEPR) theory
14. electronegativity - polar and nonpolar character of covalent bonds
15. Valency bond approach of covalent bond
---Orbital overlap concept of covalent bond
16. Bonding parameters
17. Resonance
18. Directional properties of covalent bonds
19. Metallic bonding
20. Hydrogen bonding
Ionic Bond
In an ionic bond negative ions are surrounded by positive ions and positive ions are surrounded by negative ions. NaCl does not mean each Na and Cl ions are bound to each other. It only means the proportion of the ions is 1:1.
Hydrogen Bonding
The attractive force which binds hydrogen atom of one molecule with electronegative atom (F,O or N) of another molecule is known as hydrogen bond or hydrogen bonding.
Hydrogen bonds are formed when hydrogen is bonded to strongly electronegative elements uch as F, O or N.
The size of electronegative atom should be small for formation of Hydrogen bonds. Hydrogen bonds are not formed by Cl because of its bigger size.
Example of Hydrogen bonds
HF
H2O
NH3
Influence of Hydrogen bonding on properties
.1 Association
2. Higher melting and boiling points
3. Influence on the physical state
4. Solubility
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Examples in the Chapter
Double bond
O2 molecule
CO2 molecule C forms double bond with each O atom.
CS2
Triple bond
N2 molecule
CO molecule
Exceptions to octet rule
Hydrogen molecule only 2 electrons make it stable.
Incomplete octet of central atom
LiCl
BeH2
BeCl2
BH3
BF3
LiCl 4 electrons around central Li-atom
BeCl2 4 electrons around central Be-atom
BF3 6 electrons around central B-atom
Expanded octet of the central atom
PF5 has ten around P
SF6 hs twelve around S
IF7 has fourteen electrons around I
H2SO4 12 electrons around sulphur atoms
Odd elctron molecules
Nitric oxide, NO
Nitrogen 7 shared electrons
Oxygen 8
Nitrogen dioxide, NO2(there is a coordinate bond)
Nitrogen 7
both oxygens 8
compounds of noble gases
XeF2, KrF2, XeOF2, XeOF4, XeF6
Coordinate covalent bonds
ozone
Hydronium ion
ammonia
sulphuric acid
Molecule shapes
Linear
BeF2, BeCl2, ZnCl2, HgCl2
Trigonal planar
BF3, BCl3, AlCl3
Tetrahedral
CH4, SiF4, CCl4, SiH4, NH4^+
Trigonal bipyramidal
PCl5, PF5
Octahedral
SF6
Pentagonal bipyramidal
IF7
Molecules containing lone pairs and their shapes
Three electron pairs that include lone pairs
standard shape Trigonal planar
SO2 angular or V shaped or bent shape
Four electron pairs that include lone pairs
standard shape: tetrahedral geometry
Ammonia molecule pyramidal
PCl3, NF3, H3O^+
H2O molecule
two bond pairs and two lone pairs bent or angular
same shape H2S, F2O, SCl2
Five electron pairs that include lone pairs
standard shape: trigonal bipyramidal
SF4 4 bond pairs and 1 lp distorted tetrahedron or a folded square
Chlorine triflouride 3 bp and 2 lp T shaped
Xennon difluoride XeF2 2 bp and 3 lp linear geometry
six electron pairs that include lone pairs
BrF5 5bp and 1 lp square pyramidal
XeF4 4 bp and 2 lp square planar
Polar covalent molecules
HCl, BrCl, H2O, HF
Dipole moment
HCL 1.03 D
CO2 zero
H2O 1.84 D
NH3 1.49D
BF3 zero
CCl4 zero
NF3 0.24D
Molecules described by resonance property
O3 ozone
CO2
CO
SO2
SO3
Benzene
CO3^2-
NO2 ion
Hybridization
sp
BeCl2
BeF2
BeH2
C2H2
sp^2
BCl3
C2H4
sp^3
CH4
NH3
H2O
Hydrogen bonds
HF
H2O
Ammonia NH3
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VSEPR Model
I found the tutorial in the site given below very useful understand this topic.
Molecular geometry: VSEPR http://winter.group.shef.ac.uk/vsepr/intro.html
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Molecular orbital theory
I found material from the site below to be useful to understand this topic.
Molecular Orbital Theory http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch8/mo.html
Diamagnetic and Paramagnetic substances
Atoms or molecules in which the electrons are paired are diamagnetic repelled by both poles of a magnetic. Those that have one or more unpaired electrons are paramagnetic attracted to a magnetic field. Liquid oxygen is attracted to a magnetic field and can actually bridge the gap between the poles of a horseshoe magnet. The molecular orbital model of O2 is therefore superior to the valence-bond model, which cannot explain this property of oxygen.
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web sites
The Structure, Bonding and properties of substances
http://www.docbrown.info/page04/4_72bond.htm
JEE question on dipole moment
Among the following, the molecule with the highest dipole moment is:
(A) CH-3Cl (B) CH-2Cl-2
(C) CHCl-3 (D) CCl-4
answer A
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JEE Question 2007 paper I
The percentage of p-character in the orbitals forming P–P bonds in 4 P is
(A) 25
(B) 33
(C) 50
(D) 75
Solution: (D)
Phosphorous will show sp^3 hybridisation having 75% p-character.
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JEE Question 2007 paper I
Statement - 1
Boron always forms covalent bond
Because
Statement - 2
The small size of B3^+ favours formation of covalent bond.
(A) Statement – 1 is True, Statement – 2 is True; Statement – 2 is a correct explanation for statement – 1
(B) Statement – 1 is True, Statement – 2 is True; Statement – 2 is Not a correct explanation for Statement – 1.
(C) Statement – 1 is True, Statement – 2 is False
(D) Statement – 1 is False, Statement – 2 is True
Answer: A
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JEE Question paper II 2007
Among the following metal carbonyls, the C — O bond order is lowest in
(A) [Mn(CO)-6]^+
(B) [Fe(CO)-5]
(C) [Cr(CO)-6]
(D) [V(CO)-6]^-
answer: B
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JEE 2006
If the bond length of CO bond in carbon monoxide is 1.128 A,
then what is the value of CO bond length in Fe(CO)-5?
(A) 1.15 A
(B) 1.128 A
(C) 1.72 A
(D) 1.118 A
Answer: (A)
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