The orbital angular momentum of a $p-$ electron is given as

The number of unpaired electrons in $1s^2 2s^2 2p^3$ is:

The number of waves made by a Bohr electron in an orbit of maximum magnetic quantum number $3$ is

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

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

$Be$'s $4^{th}$ electron will have four quantum numbers $(n, l, m, s)$: