The d-and f-Block Elements
Introduction to Transition Elements
Position in the Periodic Table
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Their position is in between s- and p- block elements.
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There are four rows of transition elements − 3d, 4d, 5d, and 6d. The fourth row of 6d is still incomplete.
Electronic Configuration
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General outer electronic configuration is (n −1)d1−10 ns1−2.
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But this generalization has several exceptions as there is very little difference in energy between (n − 1)d and ns orbitals. For example, Cr has electronic configuration 3d5 4s1 instead of 3d4 4s2. Cu has electronic configuration 3d10 4s1 instead of 3d9 4s2.
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Outer electronic configurations of the transition elements in the ground state are listed in the following tables:
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1st series
2nd series
Element
Atomic number
Outer electronic configuration
Element
Atomic number
Outer electronic configuration
Sc
21
3d14s2
Y
39
4d15s2
Ti
22
3d24s2
Zr
40
4d25s2
V
23
3d34s2
Nb
41
4d45s1
Cr
24
3d54s1
Mo
42
4d55s1
Mn
25
3d54s2
Tc
43
4d65s1
Fe
26
3d64s2
Ru
44
4d75s1
Co
27
3d74s2
Rh
45
4d85s1
Ni
28
3d84s2
Pd
46
4d105s0
Cu
29
3d104s1
Ag
47
4d105s1
Zn
30
3d104s2
Cd
48
4d105s2
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3rd series
4th series
Element
Atomic number
Outer electronic configuration
Element
Atomic number
Outer electronic configuration
La
57
5d16s2
Ac
89
6d17s2
Hf
72
5d26s2
Rf
104
6d27s2
Ta
73
5d36s2
Db
105
6d37s2
W
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