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 A168208 Irregular table of the number of electrons of the n-th element of the PSE in atomic shells, read by rows. 7
 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, 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, 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 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. Row sums are A000027(n). A093907(c) is the maximum number that may appear in column 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 LINKS Table of n, a(n) for n=1..99. Wikipedia, Electron configurations of the elements (data page) EXAMPLE From Felix Fröhlich, Jun 02 2019: (Start) Irregular table starts as follows, where Z denotes the atomic number: Z | Element name | Electrons per shell ----------------------------------------- 1 | Hydrogen | 1 2 | Helium | 2 3 | Lithium | 2, 1 4 | Beryllium | 2, 2 5 | Boron | 2, 3 6 | Carbon | 2, 4 7 | Nitrogen | 2, 5 8 | Oxygen | 2, 6 9 | Fluorine | 2, 7 10 | Neon | 2, 8 11 | Sodium | 2, 8, 1 12 | Magnesium | 2, 8, 2 13 | Aluminium | 2, 8, 3 14 | Silicon | 2, 8, 4 15 | Phosphorus | 2, 8, 5 16 | Sulfur | 2, 8, 6 17 | Chlorine | 2, 8, 7 18 | Argon | 2, 8, 8 19 | Potassium | 2, 8, 8, 1 20 | Calcium | 2, 8, 8, 2 21 | Scandium | 2, 8, 9, 2 22 | Titanium | 2, 8, 10, 2 23 | Vanadium | 2, 8, 11, 2 24 | Chromium | 2, 8, 13, 1 25 | Manganese | 2, 8, 13, 2 26 | Iron | 2, 8, 14, 2 27 | Cobalt | 2, 8, 15, 2 (End) CROSSREFS Cf. A173642. Sequence in context: A316841 A000003 A234398 * A333003 A352072 A365067 Adjacent sequences: A168205 A168206 A168207 * A168209 A168210 A168211 KEYWORD nonn,less,tabf AUTHOR Paul Curtz, Nov 20 2009 EXTENSIONS Redefined as an irregular table by R. J. Mathar, Dec 05 2009 Edited by Felix Fröhlich, Jun 02 2019 STATUS approved

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Last modified June 17 13:47 EDT 2024. Contains 373445 sequences. (Running on oeis4.)