Electronic Orbital Properties

Properties of Electronic Orbitals

Quantum Numbers

Item	Property
n, l, m, ms	Each electron in an atom has its own unique set of these Quantum Numbers. This set of Quantum Numbers is like the Social Security Number for the electron.
n	Shell Number = 1, 2, 3, 4, 5, 6, 7 for the known elements.
n	Radial Quantum Number
n	Principal Quantum Number
n	Decides radius and energy of an orbital
Larger n	Larger radius and larger energy
Smaller n	Smaller radius and smaller energy
l	Subshell Number = 0, 1, 2, 3, ..., n-1.
l	Azimuthal Quantum Number
l	Decides shape of an orbital
l=0	Quantum number for all s subshells
l=1	Quantum number for all p subshells
l=2	Quantum number for all d subshells
l=3	Quantum number for all f subshells
m	Magnetic Quantum Number = -l, -l+1, -l+2, ..., l-2, l-1, l.
m	Decides orientation of an orbital
ms	Electron Spin Quantum Number = -1/2 or +1/2.
ms	The Zeeman Effect in an applied magnetic field can distinguish values of this Quantum Number.
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Item	Property
n=1	Contains 1s subshell
n=2	Contains 2s, 2p subshells
n=3	Contains 3s, 3p, 3d subshells
n=4	Contains 4s, 4p, 4d, 4f subshells
Any s subshell	Contains 1 spherical orbital with no subscript
Any p subshell	Contains 3 orbitals with subscripts x, y, z
Any d subshell	Contains 5 orbitals with subscripts xy, yz, xz, x2-y2, z2
Any f subshell	Contains 7 orbitals with subscripts xyz, x(z2-y2), y(x2-z2), z(x2-y2), x3-(3/5)xr2, y3-(3/5)yr2, z3-(3/5)zr2
n	Number of subshells in the n-th shell
n2	Number of orbitals in the n-th shell
2n2	Maximum number of electrons in the n-th shell
2l+1	Number of orbitals in the l-th subshell
2l+1	Number of different m values in the l-th subshell
2(2l+1)	Maximum number of electrons in the l-th subshell
2	Maximum number of electrons in an orbital
n-1	Number of Nodes in an (n)s orbital
n	Gives the row in the periodic table for filling (n)s and (n)p subshells
n+1	Gives the row in the periodic table for filling (n)d subshells
n+2	Gives the row in the periodic table for filling (n)f subshells
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Shells

Shell Number	Property
1	contains 1 subshell: s only
2	contains 2 subshells: s and p
3	contains 3 subshells: s, p, and d
4	contains 4 subshells: s, p, d, and f
n	contains n subshells
1	contains 1 orbital: one s orbital
2	contains 4 orbitals: one s and three p orbitals
3	contains 9 orbitals: one s, three p, and five d orbitals
4	contains 16 orbitals: one s, three p, five d, and seven f orbitals
n	contains n2 orbitals
1	can hold up to 2 electrons
2	can hold up to 8 electrons
3	can hold up to 18 electrons
4	can hold up to 32 electrons
n	can hold up to 2n2 electrons
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Subshells

Subshell	Property
1s	contains 1 orbital
2s	contains 1 orbital
3s	contains 1 orbital
4s	contains 1 orbital
(n)s	contains 1 orbital
2p	contains 3 orbitals
3p	contains 3 orbitals
4p	contains 3 orbitals
(n)p	contains 3 orbitals
3d	contains 5 orbitals
4d	contains 5 orbitals
(n)d	contains 5 orbitals
4f	contains 7 orbitals
(n)f	contains 7 orbitals
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Subshell	Property
1s	can hold up to 2 electrons
2s	can hold up to 2 electrons
3s	can hold up to 2 electrons
4s	can hold up to 2 electrons
(n)s	can hold up to 2 electrons
2p	can hold up to 6 electrons
3p	can hold up to 6 electrons
4p	can hold up to 6 electrons
(n)p	can hold up to 6 electrons
3d	can hold up to 10 electrons
4d	can hold up to 10 electrons
(n)d	can hold up to 10 electrons
4f	can hold up to 14 electrons
(n)f	can hold up to 14 electrons
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Subshell	Property
1s	has electrons with n=1, l=0, m=0, ms=±1/2
2s	has electrons with n=2, l=0, m=0, ms=±1/2
2p	has electrons with n=2, l=1, m=-1,0,1, ms=±1/2
3s	has electrons with n=3, l=0, m=0, ms=±1/2
3p	has electrons with n=3, l=1, m=-1,0,1, ms=±1/2
3d	has electrons with n=3, l=2, m=-2,-1,0,1,2, ms=±1/2
4s	has electrons with n=4, l=0, m=0, ms=±1/2
4p	has electrons with n=4, l=1, m=-1,0,1, ms=±1/2
4d	has electrons with n=4, l=2, m=-2,-1,0,1,2, ms=±1/2
4f	has electrons with n=4, l=3, m=-3,-2,-1,0,1,2,3, ms=±1/2
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Filling of Subshells

Mnemonic:
The subshells fill diagonally from upper right to lower left in the chart above:

 

For an atom with 118 electrons, the electron orbital configuration would be:
The electron orbital configurations for atoms with less electrons will be truncated versions of this 118-electron configuration.

 

The total of the superscripts in an element's electron configuration equals
the total number of electrons in an atom of that element.

 

See Electron Configurations of Elements for many examples.

 

Subshell	General Order Filled(*)
Lowest Energy	1st Filled
Highest Energy	Last Filled
1s	1st
2s	2nd
2p	3rd
3s	4th
3p	5th
4s	6th(*)
3d	7th(*)
4p	8th
5s	9th(*)
4d	10th(*)
5p	11th
6s	12th(*)
4f	13th(*)
5d	14th(*)
6p	15th
7s	16th(*)
5f	17th(*)
6d	18th(*)
7p	19th
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(*) There are many exceptions to this order among the d- and f- Transition Elements
since (n+2)s, (n+1)d, and (n)f orbitals are close in energy when n is large.