Chemistry Formulas for Chemical Bonding
1.
Necessary condition for an ionic solid to be
dissolved in water
Hydration Energy > Lattice
Energy
2.
Order of melting and boiling points of certain
compounds
NaF > NaCl
> NaBr > NaI; MgO > CaO >
BaO
3.
No Bond is 100% Ionic
4.
Force of attraction between two oppositely
charged ions in vacuum (air) as per Coulombs Law
F = q1q2/r2
5.
Order of the Lattice Energy of some compounds
·
LiX > NaX > KX > RbX > CsX (where X = F, Cl, Br, I)
·
MgO > CaO > SrO > BaO
·
MgCO3 > CaCO3 > SrCO3
> BaCO3
·
BaSO4 > SrSO4 > CaSO4
> MgSO4
·
Mg(OH)2 > Ca(OH)2 >
Sr(OH)2 > Ba(OH)2
·
Bivalent Ions-Bivalent Ions > Univalent Ions-Bivalent
Ions or Bivalent Ions-Univalent Ions > Univalent Ions- Univalent Ions
6.
Example of some compounds which contains more
than one type of bond
·
NaOH, KOH, Na2CO3 (Ionic Bond, Covalent Bond)
·
CO, NH3.BF3, [Co(NH3)3Cl3] (Dative Bond, Covalent Bond)
·
NH4Cl, CuSO4, K4[Fe(CN)6],
[Cu(NH3)4]SO4
(Dative Bond, Ionic Bond, Covalent Bond)
·
CuSO4.5H2O (Hydrogen Bond, Dative Bond, Ionic Bond,
Covalent Bond)
7.
Double bond or triple bond is always shorter
than corresponding single bond
8.
As S-Orbital is smaller than P-Orbital so bond
length decrease with increase in S-character
SP3 C-H =
1.093 ร
(as in Alkanes)
SP2 C-H =
1.087 ร
(as in Alkenes)
SP C-H =
1.057 ร
(as in Alkynes)
9.
Bond length increases if size of bonded atom is
increases with given atom
HI > HBr > HCl > HF
10.
Bond distance is directly proportional to Atomic
size
11.
Order of bond strength (or bond energy) of
different hydrogen halides
H-F > H-Cl > H-Br > H-I
12.
Bond energy is directly proportional to bond
order
Triple Bond > Double Bond > Single Bond
13.
Formula of Dipole Moment
Dipole moment (ยต) = Electronic Charge (e) x Distance (d)
14.
Unit of Dipole Moment
Debye (D)
1D = 1 x 10-18e.s.u. cm
SI unit of Dipole Moment is = Coulomb-Meter (C-m)
1D = 3.336 x 10-30 C-m
15.
Dipole Moment of some substances
|
Substance with Formula
|
Dipole Moment (D)
|
|
HF
|
1.91
|
|
H2O
|
1.84
|
|
SO2
|
1.60
|
|
NH3
|
1.46
|
|
NF3
|
0.24
|
|
CH3Cl
|
1.86
|
|
HCl
|
1.03
|
|
H2S
|
1.10
|
|
HBr
|
0.78
|
|
HI
|
0.38
|
16.
Formula to calculate percentage ionic character of
covalent bond
% Ionic Character = (Observed dipole moment x 100)/Dipole moment for 100%
ionic bond
17.
Order of polarizing power of cations
Li+ > Na+ > K+ > Rb+
> Cs+
Be2+ > Mg2+ > Ca2+ > Sr2+
> Ba2+
Al3+ > Mg2+ > Na+
18.
Order of polarizing power of anions
N3- > O2- > F-
P3- > S2- > Cl-
19.
Chemistry Formula of Bond Order
Bond Order = [Nb-Na]/2
Where,
Na =
Number of electrons in antibonding molecular orbitals
Nb =
Number of electrons in bonding molecular orbitals
20.
Some molecules with their bond order, bond
length and bond dissociation energy
|
Molecule
|
Bond Order
|
Bond Length (pm)
|
Bond Dissociation Energy (kJ/mol)
|
|
F2
|
1
|
142
|
158
|
|
O2
|
2
|
121
|
498
|
|
N2
|
3
|
110
|
945
|
21.
Bond Order in compounds which exhibits Resonance
Bond Order = (Total No. of bonds between two atoms)/(Total No. of
resonating structures)
