The atomic weight of an element is double its atomic number. If there are four electrons in the $2p$ orbital,the element is:

Which one is the electronic configuration of $Fe^{2+}$?

The quantum numbers for the outermost electron of an element are given as $n = 2, l = 0, m = 0, s = +\frac{1}{2}$. The element is

The set of quantum numbers for the outermost electron for copper $(Cu)$ in its ground state is:

Compare the energies of the following sets of quantum numbers for a multielectron system:
$A. n=4, \ell=1$
$B. n=4, \ell=2$
$C. n=3, \ell=1$
$D. n=3, \ell=2$
$E. n=4, \ell=0$
Choose the correct answer from the options given below:

The maximum number of electrons that can be accommodated in a $3d$ subshell is