For hydrogen-like atoms,the average distance of an electron from the nucleus for the orbitals belonging to the $4^{th}$ orbit is minimum for:

The maximum number of electrons accommodated in $5f$ orbitals are

An element has an outermost orbital configuration of $4s^2$. What is its atomic number?

Consider the electronic configuration for neutral atoms:
$(i) \ 1s^22s^22p^63s^1$ $(ii) \ 1s^22s^22p^64s^1$
Which of the following statements is/are false?
$(a)$ Energy is required to change $(i)$ to $(ii)$
$(b)$ $(i)$ represents $Na$ atom
$(c)$ $(i)$ and $(ii)$ represent different elements
$(d)$ More energy is required to remove one electron from $(i)$ than $(ii)$

The maximum number of electrons that can be accommodated in all orbitals with quantum numbers $n = 3$ and $l = 2$ is $......$.

The number of $d$ electrons in $Fe$ is equal to which of the following?
$i$. Total number of '$s$' electrons of $Mg$
$ii$. Total number of '$p$' electrons of $Cl$
$iii$. Total number of '$p$' electrons of $Ne$
The correct option is