CHEMISTRY TEXTBOOK

Table 8.2 Electronic configuration of 3d series of d-block elements

Elements Symbol At. No. Expected electronic

configuration

Observed electronic
configuration
Scandium Sc 21 [Ar] 3d^1 4s^2 [Ar] 3d^1 4s^2
Titanium Ti 22 [Ar] 3d^2 4s^2 [Ar] 3d^2 4s^2
Vanadium V 23 [Ar] 3d^3 4s^2 [Ar] 3d^3 4s^2
Chromium Cr 24 [Ar] 3d^4 4s^2 [Ar] 3d^5 4s^1
Manganese Mn 25 [Ar] 3d^5 4s^2 [Ar] 3d^5 4s^2

Iron Fe 26 [Ar] 3d^6 4s^2 [Ar] 3d^6 4s^2

Cobalt Co 27 [Ar] 3d^7 4s^2 [Ar] 3d^7 4s^2

Nickel Ni 28 [Ar] 3d^8 4s^2 [Ar] 3d^8 4s^2

Copper Cu 29 [Ar] 3d^9 4s^2 [Ar] 3d^10 4s^1

Zinc Zn 30 [Ar] 3d^10 4s^2 [Ar] 3d^10 4s^2

Table 8.3: Oxidation states of first transition series elements

Elements Outer

electronic

configuration

Oxidation states Elements Outer

electronic

configuration

Oxidation states

Sc 3d^1 4s^2 +1, +2, +3 Fe 3d^6 4s^2 +2, +3, +4, +5, +6

Ti 3d^2 4s^2 +2, +3, +4 Co 3d^7 4s^2 +2, +3, +4, +5

V 3d^3 4s^2 +2, +3, +4, +5 Ni 3d^10 4s^2 +2, +3, +4

Cr 3d^5 4s^1 +2, +3, +4, +5, +6 Cu 3d^10 4s^1 +1, +2

Mn 3d^5 4s^2 +2, +3, +4, +5, +6, +7 Zn 3d^10 4s^2 +2

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Fill in the blanks with correct outer electronic configurations.

2 nd series

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd

Z 39 40 41 42 43 44 45 46 47 48

valence

shell

electronic

configuration

4d^1 5s^2 4d^2 5s^2 4d^4 5s^1 4d^6 5s^1 4d^8 5s^1 4d^10 5s^0 4d^10 5s^2

3rd series

La Hf Ta W Re Os Ir Pt Au Hg

Z 57 72 73 74 75 76 77 78 79 80

valence shell

electronic

configuration

5d^1 6s^2 5d^3 6s^2 5d^4 6s^2 5d^6 6s^2 5d^7 6s^2 5d^9 6s^1 5d^10 6s^2

4 th series

Ac Rf Db Sg Bh Hs Mt Ds Rg Cn

Z 89 104 105 106 107 108 109 110 111 112

valence shell

electronic

configuration

6d^1 7s^2 6d^2 7s^2 6d^4 7s^2 6d^5 7s^2 6d^6 7s^2 6d^7 7s^2 6d^8 7s^2 6d^10 7s^2