Magnetic quantum Numbers| spin | Pauli exclusion principle | Aufbau | Hunds Rule

Magnetic Quantum Numbers: When a source of electron is placed in external magnetic field which is already producing its own magnetic field causes splitting of main line spectrum in to number of lines i.e. Zeeman Effect.

And this reason (external magnetic field), force the electron to change its position and hence, magnetic quantum number gives the information about the number of preferred orientations by electron in sub shell which is given as –l to +l and total number of preferred orientations are given as 2l+1.

For, n=1, l=0, m=0 --às

n=2, l=0, 1, m=-1, 0, 1----àP_x, p_y, p_z

n=3, l=0, 1, 2 m=-2,-1, 0, 1, 2---àd_xz, d_yz, d_x2-y2, d_z2, _dxy.

Spin Quantum Number:This quantum number gives the information about the magnetic properties of substance. I.e. + 1/2 or - ½.

Pauli Exclusion Principle: No two electrons can have same four quantum numbers

For example: for some value of ‘n’ n, l, m may have same value of quantum numbers but spin should be different.

Aufbau Principle: This principle states that electrons first filled in lower energy orbital than in higher energy orbital’s.

Hunds Rule: It states that no pairing can occur in any orbital until each and every orbital has one electron in each sub shell.

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