Demonstrate that $E(eV)=\frac{1240}{}(nm).$

Sodium and mercury are currently used in lighting applications. The peak emissions are at $589nm($yellow$)$ and $436nm($blue$),$ respectively. What are the corresponding energy and frequency values in $eV$ and Hertz, respectively? Read session $1\mathrm{.}1\mathrm{.}2.$

What is the wavelength $(nm),$ energy $(eV)$ and frequency $(Hz)$ of the $n=2$ to $n=1$ electronic

What are the possible $4$ quantum numbers of an electron in a$)2p$ orbital, and b$)4$ forbital $?$

What is the electronic configuration of the elements in the groups $2$ and $17$ of the periodic table? Take advantage of the notation of electronic configuration of the noble gases $[$NG$].$ You must use Madelung $($diagonal$)$ rule: orbitals with a lower $n+/$ value are filled before those with higher $n+$ I values.