%I #22 Jun 02 2019 09:19:06
%S 1,2,2,1,2,2,2,3,2,4,2,5,2,6,2,7,2,8,2,8,1,2,8,2,2,8,3,2,8,4,2,8,5,2,
%T 8,6,2,8,7,2,8,8,2,8,8,1,2,8,8,2,2,8,9,2,2,8,10,2,2,8,11,2,2,8,13,1,2,
%U 8,13,2,2,8,14,2,2,8,15,2,2,8,16,2,2,8,18,1,2,8,18,2,2,8,18,3,2,8,18,4,2
%N Irregular table of the number of electrons of the n-th element of the PSE in atomic shells, read by rows.
%C For the n-th element in the periodic system of elements, row n of the table shows the occupancy of the K-shell, then the L-shell, then the M-shell etc.
%C Row sums are A000027(n). A093907(c) is the maximum number that may appear in column c.
%C How are rows defined when the n-th element has more than one possible electron configuration? For example, element no. 28 (Nickel) has two electron configurations, namely 2, 8, 16, 2 and 2, 8, 17, 1, and it is disputed which of them is the ground state configuration of Nickel. - _Felix Fröhlich_, Jun 02 2019
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Electron_configurations_of_the_elements_(data_page)">Electron configurations of the elements (data page)</a>
%e From _Felix Fröhlich_, Jun 02 2019: (Start)
%e Irregular table starts as follows, where Z denotes the atomic number:
%e Z | Element name | Electrons per shell
%e -----------------------------------------
%e 1 | Hydrogen | 1
%e 2 | Helium | 2
%e 3 | Lithium | 2, 1
%e 4 | Beryllium | 2, 2
%e 5 | Boron | 2, 3
%e 6 | Carbon | 2, 4
%e 7 | Nitrogen | 2, 5
%e 8 | Oxygen | 2, 6
%e 9 | Fluorine | 2, 7
%e 10 | Neon | 2, 8
%e 11 | Sodium | 2, 8, 1
%e 12 | Magnesium | 2, 8, 2
%e 13 | Aluminium | 2, 8, 3
%e 14 | Silicon | 2, 8, 4
%e 15 | Phosphorus | 2, 8, 5
%e 16 | Sulfur | 2, 8, 6
%e 17 | Chlorine | 2, 8, 7
%e 18 | Argon | 2, 8, 8
%e 19 | Potassium | 2, 8, 8, 1
%e 20 | Calcium | 2, 8, 8, 2
%e 21 | Scandium | 2, 8, 9, 2
%e 22 | Titanium | 2, 8, 10, 2
%e 23 | Vanadium | 2, 8, 11, 2
%e 24 | Chromium | 2, 8, 13, 1
%e 25 | Manganese | 2, 8, 13, 2
%e 26 | Iron | 2, 8, 14, 2
%e 27 | Cobalt | 2, 8, 15, 2
%e (End)
%Y Cf. A173642.
%K nonn,less,tabf
%O 1,2
%A _Paul Curtz_, Nov 20 2009
%E Redefined as an irregular table by _R. J. Mathar_, Dec 05 2009
%E Edited by _Felix Fröhlich_, Jun 02 2019