Question Video: Identifying an Atomic Orbital from Its Quantum Numbers Chemistry

What name is given to an atomic orbital with the quantum numbers 𝑛 = 2, 𝑙 = 1, and π‘š_𝑙 = βˆ’1?

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Video Transcript

What name is given to an atomic orbital with the quantum numbers 𝑛 equals two, 𝑙 equals one, and π‘š sub 𝑙 equals negative one?

Atomic orbitals are mathematical expressions that describe the location of an electron around the nucleus of an atom. Atomic orbitals come in different shapes and sizes. We can refer to a specific orbital using quantum numbers. The first is the principal quantum number which is given the letter 𝑛. This quantum number tells us the energy level the atomic orbital is in. 𝑛 equals two for the orbital in this question. So we know the orbital is in the second energy level.

The next quantum number is the subsidiary quantum number given the letter 𝑙. This quantum number tells us the orbital type or the subshell the orbital is located in. This spherically shaped orbital is an s-type orbital, which makes up the s subshell. These three orbitals are p-type orbitals, which make up the p subshell. For s-type orbitals, 𝑙 equals zero. And for p-type orbitals, 𝑙 equals one. 𝑙 equals one for the atomic orbital in this question. So we know it’s a p orbital.

The final quantum number π‘š sub 𝑙 is the magnetic quantum number. This quantum number tells us the orientation of the orbital. For these p orbitals, π‘š sub 𝑙 specifies which Cartesian coordinate axis the orbital is oriented along. However, to name an atomic orbital, we don’t need to know the orientation. We only need to specify the energy level and the orbital type using the number of the energy level and the letter of the orbital. So the name of the atomic orbital with the quantum numbers 𝑛 equals two, 𝑙 equals one, and π‘š sub 𝑙 equals negative one is 2p.

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