Electronic Orbital Properties

Updated 2009-03-12 00:13

Properties of Electronic Orbitals

Quantum Numbers

n, l, m, msEach 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.
nShell Number = 1, 2, 3, 4, 5, 6, 7
for the known elements.
nRadial Quantum Number
nPrincipal Quantum Number
nDecides radius and energy of an orbital
Larger nLarger radius and larger energy
Smaller nSmaller radius and smaller energy
lSubshell Number = 0, 1, 2, 3, ..., n-1.
lAzimuthal Quantum Number
lDecides shape of an orbital
l=0Quantum number for all s subshells
l=1Quantum number for all p subshells
l=2Quantum number for all d subshells
l=3Quantum number for all f subshells
mMagnetic Quantum Number = -l, -l+1, -l+2, ..., l-2, l-1, l.
mDecides orientation of an orbital
msElectron Spin Quantum Number = -1/2 or +1/2.
msThe Zeeman Effect in an applied magnetic field can distinguish values of this Quantum Number.


n=1Contains 1s subshell
n=2Contains 2s, 2p subshells
n=3Contains 3s, 3p, 3d subshells
n=4Contains 4s, 4p, 4d, 4f subshells
Any s subshellContains 1 spherical orbital with no subscript
Any p subshellContains 3 orbitals with subscripts
x, y, z
Any d subshellContains 5 orbitals with subscripts
xy, yz, xz, x2-y2, z2
Any f subshellContains 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
nNumber of subshells in the n-th shell
n2Number of orbitals in the n-th shell
2n2Maximum number of electrons in the n-th shell
2l+1Number of orbitals in the l-th subshell
2l+1Number of different m values in the l-th subshell
2(2l+1)Maximum number of electrons in the l-th subshell
2Maximum number of electrons in an orbital
n-1Number of Nodes in an (n)s orbital
nGives the row in the periodic table
for filling (n)s and (n)p subshells
n+1Gives the row in the periodic table
for filling (n)d subshells
n+2Gives the row in the periodic table
for filling (n)f subshells


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


1scontains 1 orbital
2scontains 1 orbital
3scontains 1 orbital
4scontains 1 orbital
(n)scontains 1 orbital
2pcontains 3 orbitals
3pcontains 3 orbitals
4pcontains 3 orbitals
(n)pcontains 3 orbitals
3dcontains 5 orbitals
4dcontains 5 orbitals
(n)dcontains 5 orbitals
4fcontains 7 orbitals
(n)fcontains 7 orbitals


1scan hold up to 2 electrons
2scan hold up to 2 electrons
3scan hold up to 2 electrons
4scan hold up to 2 electrons
(n)scan hold up to 2 electrons
2pcan hold up to 6 electrons
3pcan hold up to 6 electrons
4pcan hold up to 6 electrons
(n)pcan hold up to 6 electrons
3dcan hold up to 10 electrons
4dcan hold up to 10 electrons
(n)dcan hold up to 10 electrons
4fcan hold up to 14 electrons
(n)fcan hold up to 14 electrons


1shas electrons with n=1, l=0, m=0, ms=±1/2
2shas electrons with n=2, l=0, m=0, ms=±1/2
2phas electrons with n=2, l=1, m=-1,0,1, ms=±1/2
3shas electrons with n=3, l=0, m=0, ms=±1/2
3phas electrons with n=3, l=1, m=-1,0,1, ms=±1/2
3dhas electrons with n=3, l=2, m=-2,-1,0,1,2, ms=±1/2
4shas electrons with n=4, l=0, m=0, ms=±1/2
4phas electrons with n=4, l=1, m=-1,0,1, ms=±1/2
4dhas electrons with n=4, l=2, m=-2,-1,0,1,2, ms=±1/2
4fhas electrons with n=4, l=3, m=-3,-2,-1,0,1,2,3, ms=±1/2

Filling of Subshells

2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
The subshells fill diagonally from upper right to lower left in the chart above:
First is 1s, then 2s, then 2p and 3s, then 3p and 4s.
Next comes 3d, 4p, and 5s. Then comes 4d, 5p, and 6s.
After that comes 4f, 5d, 6p, and 7s. Last comes 5f, 6d, and 7p.


For an atom with 118 electrons, the electron orbital configuration would be:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10 7p6
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.


SubshellGeneral Order Filled(*)
Lowest Energy1st Filled
Highest EnergyLast Filled


(*) 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.

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