The sum of the number of angular nodes and radial nodes for a $4d$ orbital is:

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:
$(1).$ $n=4, l=2, m_l=-2, m_s=-1/2$
$(2).$ $n=3, l=2, m_l=1, m_s=+1/2$
$(3).$ $n=4, l=1, m_l=0, m_s=+1/2$
$(4).$ $n=3, l=2, m_l=-2, m_s=-1/2$
$(5).$ $n=3, l=1, m_l=-1, m_s=+1/2$
$(6).$ $n=4, l=1, m_l=0, m_s=+1/2$

The correct set of quantum numbers for the unpaired electron of a chlorine atom is:

Which one is the electronic configuration of $Fe^{2+}$?

Which of the following elements has the least number of electrons in its $M$ shell?

The energy required to remove an electron from different subshells of a $H$ atom is given below. What is the order of these energies?