Which isotope has the greatest number of protons? a pa-238 b u-240 c np-238 d pu-239

The isotope with the greatest number of protons is:

Explanation:

The number of protons is the atomic number and is a unique number for each type of element.

You can tell the number of protons searching the element in a periodic table and reading its atomic number.

Thus, this is how you tell the number of protons or each isotope

Sample       Chemical symbol  Element       atomic number   # of protons

A Pa-238       Pa                         protactinium         91                        91

B U-240         U                          uranium                 92                       92

C Np-238       Np                        neptunium            93                       93

D Pu-239        Pu                        plutonium              94                       94

it is stable as it is in group 0 which have full outer shells of electrons