For a given atomic orbital,$n = 3$. What are the possible values of $l$ and $m_l$?

(N/A) For $n = 3$,the possible values of the azimuthal quantum number $l$ range from $0$ to $(n - 1)$.
Thus,$l = 0, 1, 2$.
For each value of $l$,the magnetic quantum number $m_l$ ranges from $-l$ to $+l$ including $0$.
If $l = 0$,$m_l = 0$.
If $l = 1$,$m_l = -1, 0, +1$.
If $l = 2$,$m_l = -2, -1, 0, +1, +2$.
Total number of $m_l$ values $= 1 + 3 + 5 = 9$.