Write the electronic configuration of the following ions:
$(a) H^-$
$(b) Na^+$
$(c) O^{2-}$
$(d) F^-$

The number of correct statements from the following:
$A.$ For $1s$ orbital,the probability density is maximum at the nucleus.
$B.$ For $2s$ orbital,the probability density first increases to maximum and then decreases sharply to zero.
$C.$ Boundary surface diagrams of the orbitals enclose a region of $100\%$ probability of finding the electron.
$D.$ $p$ and $d$-orbitals have $1$ and $2$ angular nodes respectively.
$E.$ Probability density of $p$-orbital is zero at the nucleus.

Which of the following ions does not have the same electronic configuration as $Ne$?

The electronic configuration of an element is $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$. This represents:

Which of the following orbitals has a dumbbell shape?

The total number of orbitals present for principal quantum number,$n=4$ is