The number of neutrons in a nucleus of uranium 235, atomic number 92, is
- A. 92
- B. 143
- C. 235
- D. 327
Explanation
Neutron number is mass number minus atomic number, so 235 minus 92 gives 143. The mass number counts protons and neutrons together, which are collectively called nucleons. Adding the two numbers, as in the 327 distractor, has no physical meaning.