The atomic number of the element from the following with lowest 1^st ionisation enthalpy is :

Given below are two statements:

Statement I: H₂Se is more acidic than H₂Te

Statement II: H₂Se has higher bond enthalpy for dissociation than H₂Te

In the light of the above statements, choose the correct answer from the options given below:

Choose the incorrect trend in the atomic radii (r) of the elements.

The number of valence electrons present in the metal among $\mathrm{Cr}, \mathrm{Co}, \mathrm{Fe}$ and Ni which has the lowest enthalpy of atomisation is :