Question

Consider a spectral line resulting from the transition $n=5$ to $n=1$, in the atoms and ions given below. The shortest wavelength is produced by

• A. Helium atom
• B. Deuterium atom
• C. Singly ionized helium
• D. Ten times ionized sodium atom

Answer 1

The correct option is D Ten times ionized sodium atom

Wavelength emitted by transition of electrons (in hydrogen like atoms) from $n_{2}to{n}_1$ is given by the equation:
$\frac{1}{\lambda }=R{Z}^2(\frac{1}{{n_1}^2}-\frac{1}{{n_2}^2})$
which implies, $\lambda$ is inversely proportional to the square of atomic number ($Z$).
Hence, shortest wavelength is emitted by ten times ionized sodium atom with $Z=11$