Magnetic quantum number

Definition

The magnetic quantum number ($m_l$) specifies the orientation of an orbital around the nucleus. It can take on integer values between $-l$ and $+l$, where $l$ is the azimuthal quantum number.

5 Must Know Facts For Your Next Test

1. $m_l$ determines the number of orbitals and their orientation within a subshell.
2. For a given subshell with azimuthal quantum number $l$, $m_l$ can have $(2l + 1)$ possible values.
3. $m_l$ values range from $-l$ to $+l$, including zero.
4. $m_l$ is crucial for understanding the splitting of spectral lines in a magnetic field, known as the Zeeman effect.
5. The total number of orbitals in an energy level is given by $n^2$, where $n$ is the principal quantum number.

Review Questions

• What does the magnetic quantum number ($m_l$) specify?
• How many possible values can $m_l$ have for a subshell with azimuthal quantum number $l = 2$?
• Why is the magnetic quantum number important in understanding spectral line splitting?

Related terms

Principal Quantum Number:

Denoted by $n$, it indicates the main energy level occupied by an electron and determines its average distance from the nucleus.

Azimuthal Quantum Number: Denoted by $l$, it defines the shape of an orbital and can have integer values from $0$ to $(n-1)$.

Zeeman Effect: A phenomenon where spectral lines are split into multiple components in the presence of a magnetic field due to interactions involving different orientations of orbitals.