What is the atomic number of an element whose $M^{2+}$ ion has the electronic configuration $[Ar] \, 3d^8$?

How many electrons are present in an atom with atomic number $Z = 104$ for which $(n + l) = 8$?

Identify the incorrect statement from the following:

What is the number of unpaired electrons in a ferrous ion $(Fe^{2+})$?

The atomic number of the element (in ground state) having the maximum number of unpaired $3p$ electrons is:

The number of electrons with $(n+\ell)$ values equal to $3, 4$ and $5$ in an element with atomic number $(Z) = 24$ are respectively $(n =$ principal quantum number and $\ell =$ azimuthal quantum number).