Important D & f Blocks Formulas for JEE and NEET

 Page 1


  
d-BLOCK ELEMENTS & THEIR COMPOUNDS
The general electronic configuration of d-block elements is (n?1)d
1?10
ns
0?2
,
where n is the outer most shell.
GENERAL TRENDS IN THE CHEMISTRY OF TRANSITION
ELEMENTS.
Metallic character :
Nearly all the transition elements display typical metallic properties such
as high tensile strength, ductility,  malleability, high thermal and electrical
conductivity and metallic lustre. With the exceptions of Zn,Cd,  Hg and
Mn, they have one or more typical metallic structures at normal
temperatures.
The  transition elements (with the exception of Zn, Cd and Hg) are very
much hard and have low volatility.
Page 2


  
d-BLOCK ELEMENTS & THEIR COMPOUNDS
The general electronic configuration of d-block elements is (n?1)d
1?10
ns
0?2
,
where n is the outer most shell.
GENERAL TRENDS IN THE CHEMISTRY OF TRANSITION
ELEMENTS.
Metallic character :
Nearly all the transition elements display typical metallic properties such
as high tensile strength, ductility,  malleability, high thermal and electrical
conductivity and metallic lustre. With the exceptions of Zn,Cd,  Hg and
Mn, they have one or more typical metallic structures at normal
temperatures.
The  transition elements (with the exception of Zn, Cd and Hg) are very
much hard and have low volatility.
  
Melting and boiling points :
The melting and boiling points of the transition series elements are gernerally
very high.
Density :
The atomic volumes of the transition elements are low compared with the
elements of group 1 and 2. This is because the increased nuclear charge
is poorly screened the transition metals are high.
Oxidation states :
Most of transition elements show variable oxidation states. Participation
of inner (n ? 1) d-electrons in addition to outer ns-electrons because, the
energies of the ns and (n ? 1) d-subshells are nearly same.
Different oxidation states of first transition series.
Element
Outer
electronic
configuration
Oxidation states
Sc
3d
1
4s
2
+3
Ti
3d
2
4s
2
+2, +3, +4
V
3d
3
4s
2
+2, +3, +4, +5
Cr
3d
5
4s
1
+2, +3, (+4), (+5), +6
Mn
3d
5
4s
2
+2, +3, +4, (+5), +6, +7
Fe
3d
6
4s
2
+2, +3, (+4), (+5), (+6)
Co
3d
7
4s
2
+2, +3, (+4)
Ni
3d
8
4s
2
+2, +3, +4
Cu
3d
10
4s
1
+1, +2
Zn
3d
10
4s
2
+2
Page 3


  
d-BLOCK ELEMENTS & THEIR COMPOUNDS
The general electronic configuration of d-block elements is (n?1)d
1?10
ns
0?2
,
where n is the outer most shell.
GENERAL TRENDS IN THE CHEMISTRY OF TRANSITION
ELEMENTS.
Metallic character :
Nearly all the transition elements display typical metallic properties such
as high tensile strength, ductility,  malleability, high thermal and electrical
conductivity and metallic lustre. With the exceptions of Zn,Cd,  Hg and
Mn, they have one or more typical metallic structures at normal
temperatures.
The  transition elements (with the exception of Zn, Cd and Hg) are very
much hard and have low volatility.
  
Melting and boiling points :
The melting and boiling points of the transition series elements are gernerally
very high.
Density :
The atomic volumes of the transition elements are low compared with the
elements of group 1 and 2. This is because the increased nuclear charge
is poorly screened the transition metals are high.
Oxidation states :
Most of transition elements show variable oxidation states. Participation
of inner (n ? 1) d-electrons in addition to outer ns-electrons because, the
energies of the ns and (n ? 1) d-subshells are nearly same.
Different oxidation states of first transition series.
Element
Outer
electronic
configuration
Oxidation states
Sc
3d
1
4s
2
+3
Ti
3d
2
4s
2
+2, +3, +4
V
3d
3
4s
2
+2, +3, +4, +5
Cr
3d
5
4s
1
+2, +3, (+4), (+5), +6
Mn
3d
5
4s
2
+2, +3, +4, (+5), +6, +7
Fe
3d
6
4s
2
+2, +3, (+4), (+5), (+6)
Co
3d
7
4s
2
+2, +3, (+4)
Ni
3d
8
4s
2
+2, +3, +4
Cu
3d
10
4s
1
+1, +2
Zn
3d
10
4s
2
+2
  
Characteristics of Oxides and Some lons of V and Cr
Standard electrode potentials :
The value of ionisation enthalpies gives information regarding the
thermodynamic stability of the transition metal compounds in different
oxidation states. Smaller the ionisation enthalpy of the metal, the stable
is its compound.
Electrode potentials :
In addition to ionisation enthalpy, the other factors such as enthalpy of
sublimation, hydration enthalpy, ionisation enthalpy etc. determine the
stability of a particular oxidation state in solution.
The overall energy change is
?H = ?
sub
H
?
 + IE + ?
hyd
H
The smaller the values of total energy change for a particular oxidation
state in aqueous solution, greater will be the stability of that oxidation
state. The electrode potentials are a measure of total energy change.
Qualitative, the stability of the transition metal ions in different oxidation
states can be determined on the basis of electrode potential data. The
lower the electrode potential i.e., more negative the standard reduction
potential of the electrode, the more stable is the oxidation state of the
transition metal in the aqueous solution.
Page 4


  
d-BLOCK ELEMENTS & THEIR COMPOUNDS
The general electronic configuration of d-block elements is (n?1)d
1?10
ns
0?2
,
where n is the outer most shell.
GENERAL TRENDS IN THE CHEMISTRY OF TRANSITION
ELEMENTS.
Metallic character :
Nearly all the transition elements display typical metallic properties such
as high tensile strength, ductility,  malleability, high thermal and electrical
conductivity and metallic lustre. With the exceptions of Zn,Cd,  Hg and
Mn, they have one or more typical metallic structures at normal
temperatures.
The  transition elements (with the exception of Zn, Cd and Hg) are very
much hard and have low volatility.
  
Melting and boiling points :
The melting and boiling points of the transition series elements are gernerally
very high.
Density :
The atomic volumes of the transition elements are low compared with the
elements of group 1 and 2. This is because the increased nuclear charge
is poorly screened the transition metals are high.
Oxidation states :
Most of transition elements show variable oxidation states. Participation
of inner (n ? 1) d-electrons in addition to outer ns-electrons because, the
energies of the ns and (n ? 1) d-subshells are nearly same.
Different oxidation states of first transition series.
Element
Outer
electronic
configuration
Oxidation states
Sc
3d
1
4s
2
+3
Ti
3d
2
4s
2
+2, +3, +4
V
3d
3
4s
2
+2, +3, +4, +5
Cr
3d
5
4s
1
+2, +3, (+4), (+5), +6
Mn
3d
5
4s
2
+2, +3, +4, (+5), +6, +7
Fe
3d
6
4s
2
+2, +3, (+4), (+5), (+6)
Co
3d
7
4s
2
+2, +3, (+4)
Ni
3d
8
4s
2
+2, +3, +4
Cu
3d
10
4s
1
+1, +2
Zn
3d
10
4s
2
+2
  
Characteristics of Oxides and Some lons of V and Cr
Standard electrode potentials :
The value of ionisation enthalpies gives information regarding the
thermodynamic stability of the transition metal compounds in different
oxidation states. Smaller the ionisation enthalpy of the metal, the stable
is its compound.
Electrode potentials :
In addition to ionisation enthalpy, the other factors such as enthalpy of
sublimation, hydration enthalpy, ionisation enthalpy etc. determine the
stability of a particular oxidation state in solution.
The overall energy change is
?H = ?
sub
H
?
 + IE + ?
hyd
H
The smaller the values of total energy change for a particular oxidation
state in aqueous solution, greater will be the stability of that oxidation
state. The electrode potentials are a measure of total energy change.
Qualitative, the stability of the transition metal ions in different oxidation
states can be determined on the basis of electrode potential data. The
lower the electrode potential i.e., more negative the standard reduction
potential of the electrode, the more stable is the oxidation state of the
transition metal in the aqueous solution.
  
Thermochemical data (kJ mol
?1
) for the first row Transition Elements
and the Standard Electrode potentials for the Reduction of M
II
 to M
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
469
515
398
279
418
427
431
339
130
661
648
653
716
762
757
736
745
908
1310
1370
1590
1510
1560
1640
1750
1960
1730
-1866
-1895
-1925
-1862
-1998
-2079
-2121
-2121
-2059
-1.63
-1.18
-0.90
-1.18
-0.44
-0.28
-0.25
0.34
-0.76
Element (M)       Hq (M)                          H (M )        E /V 
a hyd
?
2+ ?
?
? ?
?
1 f
H
?
?
2 1
H
Formation of Coloured Ions :
Most of the compounds of transition metals are coloured in the solid form
or solution form. The colour of the compounds of transition metals may be
attributed to the presence of incomplete (n ? 1) d-subshell.
The excess of other colours constituting white light are transmitted and the
compound appears coloured. The observed colour of a substance is always
complementary colour of the colour which is absorbed by the substance.
Page 5


  
d-BLOCK ELEMENTS & THEIR COMPOUNDS
The general electronic configuration of d-block elements is (n?1)d
1?10
ns
0?2
,
where n is the outer most shell.
GENERAL TRENDS IN THE CHEMISTRY OF TRANSITION
ELEMENTS.
Metallic character :
Nearly all the transition elements display typical metallic properties such
as high tensile strength, ductility,  malleability, high thermal and electrical
conductivity and metallic lustre. With the exceptions of Zn,Cd,  Hg and
Mn, they have one or more typical metallic structures at normal
temperatures.
The  transition elements (with the exception of Zn, Cd and Hg) are very
much hard and have low volatility.
  
Melting and boiling points :
The melting and boiling points of the transition series elements are gernerally
very high.
Density :
The atomic volumes of the transition elements are low compared with the
elements of group 1 and 2. This is because the increased nuclear charge
is poorly screened the transition metals are high.
Oxidation states :
Most of transition elements show variable oxidation states. Participation
of inner (n ? 1) d-electrons in addition to outer ns-electrons because, the
energies of the ns and (n ? 1) d-subshells are nearly same.
Different oxidation states of first transition series.
Element
Outer
electronic
configuration
Oxidation states
Sc
3d
1
4s
2
+3
Ti
3d
2
4s
2
+2, +3, +4
V
3d
3
4s
2
+2, +3, +4, +5
Cr
3d
5
4s
1
+2, +3, (+4), (+5), +6
Mn
3d
5
4s
2
+2, +3, +4, (+5), +6, +7
Fe
3d
6
4s
2
+2, +3, (+4), (+5), (+6)
Co
3d
7
4s
2
+2, +3, (+4)
Ni
3d
8
4s
2
+2, +3, +4
Cu
3d
10
4s
1
+1, +2
Zn
3d
10
4s
2
+2
  
Characteristics of Oxides and Some lons of V and Cr
Standard electrode potentials :
The value of ionisation enthalpies gives information regarding the
thermodynamic stability of the transition metal compounds in different
oxidation states. Smaller the ionisation enthalpy of the metal, the stable
is its compound.
Electrode potentials :
In addition to ionisation enthalpy, the other factors such as enthalpy of
sublimation, hydration enthalpy, ionisation enthalpy etc. determine the
stability of a particular oxidation state in solution.
The overall energy change is
?H = ?
sub
H
?
 + IE + ?
hyd
H
The smaller the values of total energy change for a particular oxidation
state in aqueous solution, greater will be the stability of that oxidation
state. The electrode potentials are a measure of total energy change.
Qualitative, the stability of the transition metal ions in different oxidation
states can be determined on the basis of electrode potential data. The
lower the electrode potential i.e., more negative the standard reduction
potential of the electrode, the more stable is the oxidation state of the
transition metal in the aqueous solution.
  
Thermochemical data (kJ mol
?1
) for the first row Transition Elements
and the Standard Electrode potentials for the Reduction of M
II
 to M
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
469
515
398
279
418
427
431
339
130
661
648
653
716
762
757
736
745
908
1310
1370
1590
1510
1560
1640
1750
1960
1730
-1866
-1895
-1925
-1862
-1998
-2079
-2121
-2121
-2059
-1.63
-1.18
-0.90
-1.18
-0.44
-0.28
-0.25
0.34
-0.76
Element (M)       Hq (M)                          H (M )        E /V 
a hyd
?
2+ ?
?
? ?
?
1 f
H
?
?
2 1
H
Formation of Coloured Ions :
Most of the compounds of transition metals are coloured in the solid form
or solution form. The colour of the compounds of transition metals may be
attributed to the presence of incomplete (n ? 1) d-subshell.
The excess of other colours constituting white light are transmitted and the
compound appears coloured. The observed colour of a substance is always
complementary colour of the colour which is absorbed by the substance.
  
Magnetic Properties :
(i) Paramagnetic substances : The substances which are attracted by
magnetic field are called paramagnetic substances.
(ii) Diamagnetic substances : The substances which are repelled by
magnetic field are called diamagnetic substances. The ?spin only? magnetic
moment can be calculated from the relation :
? = ) 2 n ( n ? B.M.
where n is the number of unpaired electrons and ? is magnetic moment in
Bohr magneton (BM) units.
The paramagnetism first increases in any transition series and than
decreases. The maximum paramagnetism is observed around the middle
of the series (as contains maximum number of unpaired electrons).
Formation of Interstitial Compounds :
Transition metals form intersitial compounds with elements such as
hydrogen, boron, carbon and nitrogen.
Catalytic properties :
Many transition metals and their compounds act as good catalysts for
various reactions. Of these, the use of Fe, Co, Ni, V, Cr, Mn, Pt, etc. are
very common.
(i) The catalytic property of transition metals is due to their tendency to form
reaction intermediates with suitable reactants. These intermediates give
reaction paths of lower activation energy and, therefore, increase the rate
of the reaction.
(ii) In some cases, the transition metal catalysts provide a suitable large
surface area for the adsorption of the reactant. This increases the
concentration of the reactants at the catalyst surface and also weakens
the bonds in the reactant molecules. Consequently, the activation energy
gets lowered.
(iii) In some cases, the transition metal ions can change their oxidation states
and become more effective as catalysts.
Alloy Formation :
Alloys are hard, have high melting points and are more resistant to corrosion
than parent metals.