Which following pair of elements does NOT represent chemical twins?

Which following pair of elements does NOT represent chemical twins?
  1. $\mathrm{Nb}$ - Ta
  2. $\mathrm{Zr}-\mathrm{Rf}$
  3. $\mathrm{Mo}-\mathrm{W}$
  4. $\mathrm{Tc}-\mathrm{Re}$

Solution

Chemical twins are those in which the properties of some elements are same. Zr-Rf is not a chemical twin.

Asked in: MHT CET 2020 (13 Oct Shift 2)

Practice more Transition and Inner Transition Elements questions on Aicharya