Question

Which of the following radioisotopes is naturally occurring?

93^239Np

53^131I

102^254No

96^242Cm

Answer 1

@abb0t

Answer 2

probably the one closest to it's atomic number.

Answer 3

is it C?

Answer 4

@Australopithecus

Answer 5

First off Everything up to Cf (Californium) atomic number 98 is known to exist in nature, everything after that is assumed to be synthetically produced.

Iodine is pretty far from its natural atomic mass you could thus assume it is likely to be unstable.

The rest that are left over you can use an island of stability diagram:
http://upload.wikimedia.org/wikipedia/commons/b/bc/Island_of_Stability.svg

or go by abb0ts suggestion.

Answer 6

by assumed I mean conjectured

Answer 7

thank you