2. • THE POSITION IN PERIODIC TABLE.
• THE TRANSITION ELEMENT.
• ELECTRONIC CONFIGURATION .
• PHYSICAL PROPERTIES OF THE TRANSITION ELEMENTS .
• VARIATION IN ATOMIC AND IONIC SIZES.
• IONISATION ENTHALPIES .
• OXIDATION STATES.
• TRENDS IN THE M2+/M SEP.
• TRENDS IN THE M3+/M2+ SEP.
• TRENDS IN THE STABILITY OF HIGHER OXIDATION
3. The d-Block elements are lie in between s and
p block elements. The d-Block elements are
called transition elements because they lie
between the most electropositive s-block and
the most electronegative p-block elements
that’s why they are known as transition
element because they represent the transition
from metallic character to non-metallic
character.
4. ELECTRONIC CONFIGURATION
[n-1]d1-10 ns1-2
AT.
NO.
21 22 23 24 25 26 27 28 29 30
ELE. Sc Ti V Cr Mn Fe Co Ni Cu Zn
E.C 3d1
4s2
3d2
4s2
3d3
4s2
3d5
4s1
3d5
4s2
3d6
4s2
3d7
4s2
3d8
4s2
3d10
4s1
3d10
4s2
First [3d] Transition element series[sc-zn]
5. At. No. Element E.C
39 Y 4d1 5s2
40 Zr 4d2 5s2
41 Nb 4d4 5s1
42 Mo 4d5 5s1
43 Tc 4d6 5s1
44 Ru 4d7 5s1
45 Rh 4d8 5s1
46 Pd 4d10 5s0
47 Ag 4d10 5s1
48 Cd 4d10 5s2
At .No. ELEMENT
57 La
72 Hf
73 Ta
74 W
75 Re
76 Os
77 Ir
78 Pt
79 Au
80 Hg
E.C
5d1 6s2
5d2 6s2
5d3 6s2
5d4 6s2
5d5 6s2
5d6 6s2
5d7 6s2
5d9 6s1
5d10 6s1
5d10 6s2
Second [4d] transition series Third [5d] transition series
6. The exceptional E.C of chromium
the 4s sub shell is completely filled
but 3d sub shell is neither
completely filled nor half filled .
• To attain a filled E.C Cu gains
one e- from the d-orbital and
attains the E.C of [Ar]d10
4s1.Thus both Cr and Cu have
exceptional E.C.
7. TRANSITION ELEMENT
Elements which have partially filled [n-1]d
orbital’s in ground state or in excited state are
called transition element .
Zn ,Cd and Hg are not considered as transition
element because their ions, Zn2+,Cd2+ and Hg2+
have completely filled d-sub shell.
8. a) They show variable oxidation state.
b) They have high melting and boiling point
c) They have a great tendency to form
complexes.
d) They form alloys.
e) They are electropositive in nature.
f) Most of the transition elements form coloured
compounds.
g) Their compounds are generally paramagnetic
in nature.
9. Trends in the properties of transition
elements
Atomic and Ionic radii
The atomic radii of d-block elements in
a series decrease with increase in atomic
number as the nuclear charge increases
whereas the shielding effect of d-e- is
small.
At the end of the period, there is slight
increase in the atomic radii.
Sc Ti V Cr Mn Fe Co Ni Cu Zn
162 147 134 127 126 126 125 124 124 138
10. IONISATION ENTHALPIES
• The ionisation enthalpy gradually increase
with increase in atomic number along a
given transition series.
EX –The increasing ionisation enthalpies are
due to increased nuclear charge with
increase in atomic number which reduces
the size of the atom making the removal of
outer e- difficult.
11. Metallic character
• Except mercury which is a liquid ,all the
transition element have typical metallic
structure[hcp, ccp or bcc] They exhibits all the
characteristics of metals. For ex- They are
hard, lustrous, malleable and ductile etc.
Melting and Boiling point
• The transition metals have very high melting
and boiling point .The melting points of the
transition metals rise to a maximum and then
fall as the atomic number increases.
12.
13. .
Sc Ti V Cr Mn Fe Co Ni Cu Zn
+1
+2 +2 +2 +2 +2 +2 +2 +2 +2
+3 +3 +3 +3 +3 +3 +3 +3
+4 +4 +4 +4 +4 +4 +4
+5 +5 +5
+6 +6 +6
+7
14. • A very low value for Electrode [sc3+/Sc2+] reflects
the stability of Sc3+ ion which a noble gas
configuration
• For Sc Sc[21]= [Ar]3d1 4s2
• Sc[21]2+ = [Ar] 3d1 4s0
• Sc [21]3+= [Ar] 3d0 4s0
• The highest value for Zn is on account of very
high stability of Zn2+ ion with d10 configuration.
15. • There is no regular trend in electrode [M2+/M]
values. This is because their ionization enthalpies
and sublimation enthalpies do not show any
regular trend.
• The general trend towards less negative electrode
values along the series is due to the general
increase in the sum of first and second ionization
enthalpies.
• Cu shows a unique behaviour in the series as it is
the only metal having positive value for
electrode.
Reason = As its sublimation and I.E does
compensate with hydration enthalpy.
