Uranium is a radioactive element that is highly unstable and it has a half-life of 4.5 billion years. Uranium comes in many different forms (shown below). Looking at the nuclear notations below, what is the neutron number of both of the elements below? What is the relationship of the two elements below?
A: U-235 has 235 neutrons, U-238 has 238 neutrons and they are isotopes of each other.
B: U-235 has 143 neutrons, U-238 has 146 neutrons and they are isotopes of each other.
C: U-235 has 235 neutrons, U-238 has 238 neutrons and they are ions of each other.
D: U-235 and U-238 have 92 neutrons and they are ions of each other.
