hydrogen has three isotopes: Protium ( 1 proton) , Deuterium ( 1 proton and 1 neutron), and tritium (1 proton and 2 neutrons).

which of these isotopes is most electronegative and why?

Dear Janani,

Protium would have the highest electronegativity value followed by Deutrium & then finally tritium ..

The electronegativity decreases in the order..

       Protium(₁H¹)>Deutrium(₁H²)>Tritium(₁H³)

This is because electronegativity is the tendency to attract the shared pair of electrons towards a particular atom..Now for Protium(₁H¹) it has one proton(+ve charged) & so it could attract the electrons effectively towards itself but in deutrium there is an added neutral charge in the form of a neutron which increases the size thus reduces the electronegativity tendency of the deutrium atom & similarly for tritium..!!

If you still have any doubts then please ask them all so as to clarify them..!!

If you loved the answer then please do not forget to approve it by clicking on "Yes" below..!!

as we increase the no. of electrons in s orbital, we have a strong shielding from s orbital..... so net effective charge on the adjacent atom's electrons decreses....hence its electronegativity decreses.....

Thus, Protium has largest electro-vetivity......