How many neutrons are in #""^239 Pu#?

1 Answer
Jun 4, 2016

There are #145# neutrons in the #""^239Pu# nucleus.

Explanation:

You specified elemental plutonium. Thus we know for a fact that #Z# #=# #94#. Since we have the mass number specified by the isotope notation, there are #239-94# massive, neutral particles in the plutonium nucleus.

To what does #Z# refer?