Question

which have more stable elements, s block or d block?​

Answer 1

D block elements tend to have a more stable outer ring of electrons, when you reach D block elements they start adding electons to inner rings rather than outer so the added electrons create more stability. S block however are still lacking electrons so group 1 elements wish to lose their electrons as quickly as possbile making them very reactive, and group 7 wish to gain an electron. 

Answer 2

Step-by-step explanation:

D block elements tend to have a more stable outer ring of electrons, when you reach D block elements they start adding electons to inner rings rather than outer so the added electrons create more stability. S block however are still lacking electrons so group 1 elements wish to lose their electrons as quickly as possbile making them very reactive, and group 7 wish to gain an electron.

The reactivity of elements reduces as you move from left to right in a periodic table. S-block elements have one or two electrons in the outer most shell (valence shell) which makes them easier to move/share while reacting with other elements. On the other hand, in D-block the valence shell electron increases and its gets litter bit harder for them to react as compare to S-block elements.