Electronic Configuration of Elements

In a given atom no two electrons can have the same values for all the four quantum numbers. This is called

An ion has $18$ electrons in the outermost shell is:

If n = 6, the correct sequence for filling of electrons will be :

Number of unpaired electrons in ${\mathrm{N}}^{2+}$ is

For which one of the following sets of four quantum numbers, an electron will have the highest energy?

Write the electronic configurations of the noble gases starting from helium and predict their atomic numbers. 

What does Hund's rule for maximum multiplicity state? 

Write the electronic configuration of the following elements. 

According to Pauli's exclusion principle, what is the maximum number of electrons that can be present in d-orbitals and f-orbitals? Explain. 

Which one of the following (a or b) electronic configurations is more stable and why? 

(a) $3{\mathrm{d}}^{4}4{\mathrm{s}}^2$

(b) $3{\mathrm{d}}^{5}4{\mathrm{s}}^1$

How is the order of the energy of the atomic orbitals established? 

Pairing of electrons in degenerate orbitals takes place only when the degenerate orbitals are filled with one electron each.

Any two electrons in an atom can have maximum of three quantum numbers same.

Among $4\mathrm{p}, 4\mathrm{s}, 3\mathrm{p}$ and $3\mathrm{d}$ orbitals, $3\mathrm{d}$ orbital has the least energy.

Energy is absorbed when the electron jumps from K to L energy shells.

What is anti-penultimate shell?

In chromyl chloride, the number of d-electrons present on chromium is same as in (Given at no. of $\mathrm{Ti} : 22, \mathrm{V} : 23, \mathrm{Cr} : 24, \mathrm{Mn} : 25, \mathrm{Fe} : 26$)

Write short notes on following:
(i)Afbau's principal.
(ii)Paulis exclusion principle.