The presence of three unpaired electrons in a nitrogen atom is explained by .......

The set of quantum numbers for the $19^{th}$ electron in chromium $(Cr)$ is:

Which of the following statement$(s)$ is/are wrong?

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).

When the $3d$ orbital is completely filled,the next entering electron will be in the ....... orbital.

Explain the meaning of the $+ve$ and $-ve$ signs in the context of the wave function $\psi$ for an electron.