Which of the following group elements do not form hydrides?

 

Question:

Which of the following group elements do not form hydrides?

(1) Group 7&8

(2) Group 7&6

(3) Group 6&8

(4) All above

Answer: 

4th option

Solution:

Hydride Gap:

In d-block,There is a hydride gap where elements do not form hydrides. the metals of group 7, 8 and 9 have low affinity for hydrogen in their normal oxidation state.Therefore, the metals of group 7, 8 and 9 in the periodic table do not form hydrides and this region of periodic table  (group 7, 8 and 9) is referred to as the hydride gap.