Which of the Following Is a Radioactive Isotope?
A) ${ } _ { 10 } ^ { 20 } \mathrm { Ne }$

Multiple Choice

Which of the following is a radioactive isotope?

A) ${ } _ { 10 } ^ { 20 } \mathrm { Ne }$
B) ${ } _ { 94 } ^ { 239 } \mathrm { Pu}$
C) ${ } _ { 50 } ^ { 118 } \mathrm { Sn }$
D) ${ } _ { 20 } ^ { 40 } \mathrm { Ca }$
E) ${ } _ { 57 } ^ { 139 } \mathrm { La }$