* Configurations of elements 109 and above are not available. Predictions from reliable sources have been used for these elements.
*
Grayed out electron numbers indicate subshells filled to their maximum.
* Bracketed noble gas symbols on the left represent inner configurations that are the same in each period. Written out, these are:
:: He, 2,
helium
Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...
: 1s
2
:: Ne, 10,
neon
Neon is a chemical element; it has symbol Ne and atomic number 10. It is the second noble gas in the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of ...
: 1s
2 2s
2 2p
6
:: Ar, 18,
argon
Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...
: 1s
2 2s
2 2p
6 3s
2 3p
6
:: Kr, 36,
krypton
Krypton (from 'the hidden one') is a chemical element; it has symbol (chemistry), symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace element, trace amounts in the Earth's atmosphere, atmosphere and is of ...
: 1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6
:: Xe, 54,
xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...
: 1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
6
:: Rn, 86,
radon
Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only Rn has a sufficiently long half-life (3.825 days) for it to b ...
: 1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
6 6s
2 4f
14 5d
10 6p
6
:: Og, 118,
oganesson
Oganesson is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint ...
: 1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
6 6s
2 4f
14 5d
10 6p
6 7s
2 5f
14 6d
10 7p
6
* Note that these electron configurations are given for neutral atoms in the gas phase, which are not the same as the electron configurations for the same atoms in chemical environments. In many cases, multiple configurations are within a small range of energies and the small irregularities that arise in the d- and f-blocks are quite irrelevant chemically.
The construction of the periodic table ignores these irregularities and is based on ideal electron configurations.
* ''Note the non-linear shell ordering, which comes about due to the different energies of smaller and larger shells.''
References
See list of sources at
Electron configurations of the elements (data page).
{{DEFAULTSORT:Periodic Table (Electron Configurations)
Electron configurations