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

Write the electronic configuration of chromium $(Cr)$ and copper $(Cu)$. Give reasons for the observed configurations of $Cr$ $(Z = 24)$ and $Cu$ $(Z = 29)$.

In an atom having $2$ $K$,$8$ $L$,$8$ $M$ and $2$ $N$ electrons,the number of electrons with $m=0$ and $s=+\frac{1}{2}$ is $:-$

Which of the following electronic configurations is not possible according to Hund's rule?

The number of unpaired electrons in cobalt atom is (atomic number of $Co = 27$)

The electrons identified by quantum numbers $n$ and $l$ :
$A. n=4, l=1$ $B. n=4, l=0$
$C. n=3, l=2$ $D. n=3, l=1$
can be placed in order of increasing energy as :