Which of the following set of quantum numbers is correct for the $19^{th}$ electron of chromium?
$n$ $l$ $m$ $s$

In which of the following pairs of orbitals is the probability of finding the electron zero in the $XY$ plane?

For which of the following sets of four quantum numbers,an electron will have the highest energy?
$n$ $l$ $m$ $s$

What is meant by electronic configuration?

The correct set of quantum numbers for the unpaired electron of $Cu$ atom is

$(i)$ Write the electronic configurations of the following ions:
$(a)$ $H^{-}$
$(b)$ $Na^{+}$
$(c)$ $O^{2-}$
$(d)$ $F^{-}$
$(ii)$ What are the atomic numbers of elements whose outermost electrons are represented by
$(a)$ $3s^{1}$
$(b)$ $2p^{3}$ and
$(c)$ $3p^{5}$?
$(iii)$ Which atoms are indicated by the following configurations?
$(a)$ $[He] 2s^{1}$
$(b)$ $[Ne] 3s^{2} 3p^{3}$
$(c)$ $[Ar] 4s^{2} 3d^{1}$