When an electron transitions from the $6^{th}$ orbit to the $2^{nd}$ orbit in a $H$ atom,what is the total number of spectral lines (excluding the Balmer series) produced?

Energy of an electron in the ground state of the hydrogen atom is $-2.18 \times 10^{-18} \ J$. Calculate the ionization enthalpy of atomic hydrogen in terms of $J \ mol^{-1}$.

What is the wavelength of light required to raise an electron in the $O^{7+}$ ion from $n=1$ shell to $n=2$ shell in $nm$?

Bohr's model can explain:

For a hydrogen $(H)$ atom,what will be the wavelength (in $nm$) associated with the transition of an electron from the infinite energy level to the first energy level? (Rydberg constant = $1.097 \times 10^{7} \ m^{-1}$)

What is the energy of an electron in the stationary state corresponding to $n=2$?