Define principal quantum number (n)

Define principal quantum number (n).
(ii) Write the electronic configuration of Cr+
[Atomic number of Cr = 24]
(iii) Define Pauli’s Exclusion principle.

Principal quantum number tells the principal energy level or shell to which the electron belongs. It gives the information about the distance and the energy of the electron.
(ii) Cr+ = 1${{s}^{2}}$2${{s}^{2}}$2${{p}^{6}}$3${{s}^{2}}$3${{p}^{6}}$3${{d}^{5}}$
(iii) Pauli’s Exclusion principle states that no two
electrons in an atom can have the same set of four quantum numbers