How would you account for the irregular of ionisation enthalpies (first) in the first series of the transition elements?

(i) Which of the first row transition metal exhibit +7 oxidation state? (ii) How would you account for the irregular variation of 1st and 2nd ionisation enthalpies in the 1st series of transition elements ? (iii) What are interstitial compounds ? (iv) Give two uses of potassium permanganate.

Assing a reason for each of the following observation : (i) The transition metals (with the exception of Zn, Cd and Hg) are hard and have high melting and boiling points (ii) The ionisation enthalpies (first and second) in the first series of the transition elements are found to vary irregularly

How would you account for the following? (i) The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding member of the second (4d) serie (ii) Because oxygen and fluorine are highly electronegative elements and small in size.

The first ionisation energies of the elements of the transition series.

Why is enthalpy of atomisation is the lowest for Zn in 3d series of transition elements ?

The CORRECT order of first ionisation enthalpy is :