Metallic character of transition metals .

1) Electrical and thermal conductivity

• These elements are good conductors due to availability of mobile / free / delocalized electrons involved in metallic bonding.

2) Hardness

• They are generally hard ( cannot be cut with a knife) and brittle.
• Hardness is due to strong metallic bond between the atoms .
• The greater the number of unpaired electrons in the valence shells , the stronger the metallic bonds and hence the greater the hardness . E.g Cr ,Mo and W have the maximum number of unpaired electrons hence very hard . Zn , Cd and Hg have no unpaired electrons therefore not very hard .

3) Crystal structure

• Transition elements have a simple hexagonal close-packed (hcp) , cubic close-packed (ccp) and bold centered cubic (bcc) lattice which are characteristics of metals .

4) Alloy formation

• Most transition elements have almost same size and hence atoms of one metal can be replaced with atoms of another metal . This leads to formation of alloys. E.g when manganese is dissolved in molten iron ,the solution manganese-iron alloy is formed.
• Alloys are hard , have high melting points and mostly more resistant to corrosion.

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