Question

The nucleus of uranium ${}_{92}{\text{U}}^{235}$ contains

• A. $143$ protons and $92$ neutrons
• B. $92$ protons and $143$ neutrons
• C. $90$ protons and $145$ neutrons
• D. $145$ protons and $90$ neutrons

Answer 1

The correct option is B $92$ protons and $143$ neutrons

The number of protons is represented by the atomic number $Z=92$.

The number of neutrons, $N=A-Z$

$\Rightarrow N=235-92$

$\Rightarrow N=143$

Hence, option $\left(B\right)$ is correct.