Characteristics of transition elements

Transition elements are metals.They are less reactive than metals of s block
The characteristics are
1)They exhibit variable valence
Reason : The core of the metal atom is stable. So it may lose one are more electrons and thus variable valence.
2) Their ion are coloured
Reason: presence of unfilled d orbital
3) They're from complexes
Reason : the d orbital involve in co-ordinate bond formation.
4) They give interstitial compounds
Reason : Non metal atoms enter into interstitial spaces of the metal particles
5)the metals or their oxides are used as catalyst
Reason : Free valencies are left over on finely divided metal properties.

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