Chemistry

Which pair of symbols below show different isotopes of the same element?

(A) 3918A and 3919R
(B) 6027X and 5928Y
(C) 126L and 146L
(D) 3717X and 3717X
(E) 32E and 31G
Chemistry

Which of the following isotopes has the greatest number of neutrons?

(A) 35Cl
(B) 31P
(C) 40Ar
(D) 41Ca
(E) 14C