chemistry of d block elements

1. D BLOCK
ELEMENTS
MS. J. PRINCESS GRACIA
DEPARTMENT OF CHEMISTRY,
BON SECOURS COLLEGE FOR WOMEN, THNJAVUR.

2. 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d10
1st
series
Sc Ti V Cr Mn Fe Co Ni Cu Zn
2nd
series
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd
3rd
series
La Hf Ta Pd Rs Os Ir Pt Au Mg

3. TRANSITION
STATE ELEMENTS :
If a ‘d’ subshell is partly filled the elelments
are known as ‘d’ block elements (or) transition
elements.
They consists of 3 Rows
 1st Transition Series
 2nd Transition Series
 3rd Transition series

4. Electronic Configuration:
1st series 3d^1-10 4s^2
2nd series 4d^1-10 5s^2
3rd series 5d^1-10 6s^2
Metallic Character:
All the transition elements are Metals.
They are moliable and ductile.
They form alloys.
They are hard and brittle.

5. Molar Volume and Density:
Molar volume decrease due to increase in nuclear charge.
Molar volume decrease the density increases.
Atomic radii:
Atomic radii and ionic radii decreases with in increase the
atoms number.
Due to increase in nuclear charge.

6. Ionisation Energy:
 Ionisation energy increase with in increase the atomic number.
 Due to increase in nuclear charge.
Reactivity :
All transition elements have smaller tendency to react.
They always tent to be unreactive.
Unreactive elements (Pt,Au)

7. Oxidation State:
They are variable oxidation states.
 Sc - +2,+3
 Ti - +2,+3,+4
 V - +2,+3,+4,+5
 Cr - +2,+3,+4,+5,+6
 Mn - +2,+3,+4,+5,+6,+7

8. Standard Electrode Potential:
 Generally negative compared to the potential of Standard
Hydrogen Electrode(SHE).
Example:
Scandium (-2.10)V ,Chromium(-0.74)V
Reducing Property:
 Except copper all the ‘d’ block elements are oxidised easily.
 To their ions (cations(+1)) in aqueous solution.

9. Colour :
 ‘d’ block elements are coloured in the solid or solution
state.
Example :
 Scandium Sc^3+ -colourless
 copper Cu^2+ -3d^104s^1- coloured
3d^94s^0 - coloured

10. Magnetic Properties:
‘d’ block elements are paramagnetic.
This paramagnetic arises due to the presence of unpaired electrons.
No unpaired electrons μeff = 0.They are called diamagnetic
substances.
The magnetic moment due to unpaired electrons spins are
alligned parallel to the external magnetic field.These
elements are said to be ferromagnetic substances.

11. Catalytic Property :
‘d’ block elements are good catalyst
example: Pt, Fe, Ni.
Transition metal also have good catalytic property(v2o5).
Iron is the good catalyst for Haber’s process.

12. Tendency to form complex’s:
 ‘d’ block metals are almost unique in their tendency to
form co ordination complex’s.This tendency is due to two
factors
 very small size of cation ,
 very high positive charge.

13. Ms.J.Princess Gracia
Department of
CHEMISTRTY
Bon Secours College for
Women,Thanjavur.