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:

option D: Pu-239, with 94 protons

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