In the $n^{th}$ quantum level,the number of electronic subshells is

According to the Aufbau principle,what is the correct order of energy for $3d$,$4s$,and $4p$ orbitals?

Which of the following statements is not correct?

Number of electrons in the outermost orbit of the element of atomic number $15$ is

Given:
$(A)\ n = 5, m_l = +1$
$(B)\ n = 2, l = 1, m_l = -1, m_s = -1/2$
The maximum number of electron$(s)$ in an atom that can have the quantum numbers as given in $(A)$ and $(B)$ are respectively:

The five valence electrons of $P^{15}$ are labeled as $A, B, X, Y, Z$ as shown in the figure. If the spin quantum number of $B$ and $Z$ is $+\frac{1}{2}$,identify the group of electrons that share three identical quantum numbers.