In whichone of thefollowing pairsthe twospeciesare bothisoelectronic andisotopic (atomicnumberCa = 2 , Ar = 18 , K = 19 mg = 12 ,fe = 26 , Na=11 )

In whichone of thefollowing pairsthe twospeciesare bothisoelectronic a

1.	In whichone of thefollowing pairsthe twospeciesare bothisoelectronic andisotopic (atomicnumberCa = 2 , Ar = 18 , K = 19 mg = 12 ,fe = 26 , Na=11 )
Answer» `.^(40)Ca^(2+)` and `.^(40) Ar` `.^(39) K^(+)` and `.^(40) K^(+)` `.^(56) Fe^(3+)` and `.^(57) Fe^(2+)` `.^(23)Na` and `.^(24) Na^(+)` ANSWER :B