Question

39. Variable valency is exhibited by
1) Normal elements
2) Metallic elements
3) Transitional elements
4) Non-metallic elements
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Answer 1

Answer:

Variable valency is often exhibited by 3) Transition elements (viz. D-Block elements) because the d-orbital electrons often are weakly bounded to their nucleus, so losing and gaining of electrons often occurs in the crystal of covalent Compound of these elements and hence due to this character they exhibit variable valency and it's application is their use as a catalysts in most reactions.

Answer 2

Answer:

3) Transitional elements