An element of atomic number $Z$ is in the ionized hydrogenic ground
state. The largest wavelength that can convert it to a fully ionized state is 3.65 nm . Select the correct statement(s). $\left(1 \mathrm{~nm}=10^{-5}\right.$
m and take the ionization energy of the hydrogen atom to be 13.60
eV.)

• A

  Its potential energy is 680 eV .
• Correct answer
  B

  $Z=5$
• Correct answer
  C

  Its kinetic energy is 340 eV .
• D

  Its Bohr radius is 0.1 nm .

Hence, the correct answer is options: 'B', 'C'.