How many electrons in an atom can have the quantum numbers $n = 3, l = 2, m = +2, s = +1/2$?

What is the maximum number of electrons that can be accommodated in a shell with principal quantum number $n = 4$?

For a one-electron atom,the set of allowed quantum numbers is

The total maximum number of electrons possible in $3d$,$6d$,$5s$,and $4f$ orbitals with $m_l$ (magnetic quantum number) value $-2$ is

Arrange the following in the increasing order of their energy:
$(i)$ $n = 2, l = 0, m_l = 0, m_s = +\frac{1}{2}$
$(ii)$ $n = 2, l = 1, m_l = +1, m_s = -\frac{1}{2}$
$(iii)$ $n = 3, l = 2, m_l = +1, m_s = -\frac{1}{2}$
$(iv)$ $n = 3, l = 1, m_l = -1, m_s = +\frac{1}{2}$

For an electron in the $d$-orbital, the orbital angular momentum is