Structure of At...

What principle is violated here?

Maximum number of electrons in a subshell of an atom is determined by the following:

Designations of some orbitals are given below. Arrange the orbitals with possible designations in the order in which they are filled with electrons $6s,\ 8p,\ 7s,\ 4d,\ 2p,\ 3d,\ 3f,\ 4f$.

For the hydrogen atom, the energy of the electron is defined by the factor $E_n=-13.58/n^2 eV$. Here n is positive integer. The minimum quantity of energy which it can absorb in its primitive stage is:

The total number of electrons that could be held in a sub-level with azimuthal quantum number = 2 is :

The maximum number of electrons in a shell with the principal quantum number =  4 is :

Which letter orbital corresponds to $l$ = 2?

Which color of light has the highest energy?

The ratio of the energy of photon of $2000 A^0$ wavelength to that of $4000 A^0$ wavelength is:

An element $X$ combines with oxygen to form compounds $P$ and $Q$. If the ratio of the valency of element $X$ in $P$ to element $X$ in $Q$ is $3 : 5$ respectively, what could be the probable compounds $P$ and $Q$?