Write all of the allowed sets of quantum numbers (n, ℓ, and m_\ell) for a 3p orbital.
Strategy The 3p designation tells us the values of the n and ℓ quantum numbers, and we can use the relationship between ℓ and m_\ell to determine the possible values of m_\ell.
The “3” in “3p” tells us that the orbital must have n = 3, and the “p” tells us that ℓ = 1. Possible values for m_\ell range from −ℓ to +ℓ; in this case, that gives us ℓ = −1, 0, or +1. So we have three possible sets of quantum numbers for a 3p orbital: n = 3, ℓ = 1, m_\ell = −1; n = 3, ℓ = 1, m_\ell = 0; and n = 3, ℓ = 1, m_\ell = 1.
Check Your Understanding An orbital has quantum numbers of n = 4, ℓ = 2, m_\ell = −1. Which type of orbital (1s, etc.) is this?