All of the isotopes listed have the same number of electrons, which is determined by the atomic number of the element.
Pa-238 and NP-238 have 91 electrons each because they are both isotopes of the element Protactinium, which has an atomic number of 91.
U-240 has 92 electrons because it is an isotope of Uranium, which has an atomic number of 92.
PU-239 also has 94 electrons because it is an isotope of Plutonium, which has an atomic number of 94.
Therefore, all of the isotopes listed have the same number of electrons, which is determined by the atomic number of the element.
To know more about isotopes refer to this link