Which of the following sets of quantum numbers is not possible?

Consider the hypothetical situation where the azimuthal quantum number,$l$,takes values $0, 1, 2, \ldots, n+1$,where $n$ is the principal quantum number. Then,the element with atomic number

Arrange the electrons represented by the following sets of quantum numbers in the decreasing order of energy.
$(i) \ n = 4, l = 0, m_l = 0, m_s = +\frac{1}{2}$
$(ii) \ n = 3, l = 1, m_l = 1, m_s = -\frac{1}{2}$
$(iii) \ n = 3, l = 2, m_l = 0, m_s = +\frac{1}{2}$
$(iv) \ n = 3, l = 0, m_l = 0, m_s = -\frac{1}{2}$

If $n$ and $l$ are principal and azimuthal quantum numbers respectively,then the expression for calculating the total number of electrons in any energy level is:

The electronic configuration $1s^2 2s^2 2p_x^1 2p_y^1 2p_z^1$ corresponds to which of the following elements?

The number of orbitals in the $d$ sub-shell is