Uranium is an element with three naturally occurring isotopes: 238U, 235U, and 234U. This means that 238U, which has a mass number of 238 has more than 235 u which has a mass number of 235.

The correct answer is - neutrons.

Explanation:

Uranium has various isotopes found naturally that are three 238U, 235U, and 234U. Uranium has an atomic number of 92 which means there are 92 protons and 92 electrons in the atomic structure.

Isotopes have the same number of protons but a different number of neutrons that can vary from 141 to 146. U-238 has 146 neutrons in the nucleus, whereas 235 U has 143 neutrons.

that's what i got you can count the number of atoms

i'm wiling to try and you : )