Beryllium's fourth electron will have the four quantum numbers :

Find the number of electron pairs in $P$ atom with $l = 1$ and $m = 0$.

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

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

What is the maximum number of orbitals that can be identified with the following quantum numbers?
$n = 3, l = 1, m_l = 0$

The number of given orbitals which have electron density along the axis is $..........$. $p_{x}, p_{y}, p_{z}, d_{xy}, d_{yz}, d_{xz}, d_{z^2}, d_{x^2-y^2}$