The electronic configuration of the phosphide ion is similar to which of the following?

Few statements are given regarding nodes in the orbitals. Mark the statement which is not correct.

The number of $d-$ electrons in $Fe^{2+} \ (Z = 26)$ is not equal to the number of electrons in which one of the following?

What is the total number of orbitals associated with the principal quantum number $n = 3$?

The number of radial nodes in a $2s$ orbital is equal to that in a ........ orbital.

The following sets of quantum numbers represent four electrons in an atom:
$(i)$ $n = 4, l = 1$ $(ii)$ $n = 4, l = 0$
$(iii)$ $n = 3, l = 2$ $(iv)$ $n = 3, l = 1$
The sequence representing the increasing order of energy is: