The orbital angular momentum of an electron in a $d$ orbital is equal to:

In a potassium atom,the electronic energy levels are in the following order:

The quantum numbers of six electrons are given below. Arrange them in order of increasing energies. If any of these combination$(s)$ has/have the same energy,list them:
$(1).$ $n=4, l=2, m_l=-2, m_s=-1/2$
$(2).$ $n=3, l=2, m_l=1, m_s=+1/2$
$(3).$ $n=4, l=1, m_l=0, m_s=+1/2$
$(4).$ $n=3, l=2, m_l=-2, m_s=-1/2$
$(5).$ $n=3, l=1, m_l=-1, m_s=+1/2$
$(6).$ $n=4, l=1, m_l=0, m_s=+1/2$

$Ge$ $(Z=32)$ in its ground state electronic configuration has $x$ completely filled orbitals with $m_{l}=0$. The value of $x$ is ..... .

The quantum number/s needed to describe an electron fully in an atom is/are:

The arrangement of orbitals on the basis of energy is based upon their $(n + l)$ value. Lower the value of $(n + l)$,lower is the energy. For orbitals having same values of $(n + l)$,the orbital with lower value of $n$ will have lower energy.
$(I)$ Based upon the above information,arrange the following orbitals in the increasing order of energy.
$(a)$ $1s, 2s, 3s, 2p$
$(b)$ $4s, 3s, 3p, 4d$
$(c)$ $5p, 4d, 5d, 4f, 6s$
$(d)$ $5f, 6d, 7s, 7p$
$(II)$ Based upon the above information,solve the questions given below:
$(a)$ Which of the following orbitals has the lowest energy? $4d, 4f, 5s, 5p$
$(b)$ Which of the following orbitals has the highest energy? $5p, 5d, 5f, 6s, 6p$