A335105 - OEIS

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A335105

Irregular triangle read by rows in which row n lists the partial sums of shell numbers and respective number of electrons for all occupied shells of the n-th element of the periodic table of the elements.

1, 2, 1, 3, 1, 3, 5, 6, 1, 3, 5, 7, 1, 3, 5, 7, 9, 10, 1, 3, 5, 7, 9, 11, 1, 3, 5, 7, 9, 12, 1, 3, 5, 7, 9, 13, 1, 3, 5, 7, 9, 14, 1, 3, 5, 7, 9, 15, 1, 3, 5, 7, 9, 15, 18, 19, 1, 3, 5, 7, 9, 15, 18, 20, 1, 3, 5, 7, 9, 15, 18, 20, 23, 24, 1, 3, 5, 7, 9, 15, 18, 20, 23, 25

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The rows provide a way to distinguish the elements.

Electron Configurations for elements after Nobelium (atomic number 102), whose configuration of [RN] 5f14 7s2 comprises the last row of sequence, are at present unknown (see CRC Handbook in References).

REFERENCES

Darleane C. Hoffman, Diana M. Lee, and Valeria Pershina, Transactinides and Future Elements, in Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands (2006).

Catherine E. Housecroft and Alan G. Sharpe, Inorganic Chemistry (5th ed.). Pearson Education Limited. Harlow, England. (2018).

John R. Rumble (ed.), CRC Handbook of Chemistry and Physics, 100th edition. CRC Press. Boca Raton, Florida, 2019; Section 1, Electron Configuration and Ionization Energy of Neutral Atoms in the Ground State.

LINKS

David Williams, Table of n, a(n) for n = 1..200, for rows 1-23 and part of 24

Wikipedia, Electron shell

EXAMPLE

Lithium 1s2 2s1

1+2+2+1

1,3,5,6

Thus:

Hydrogen 1s1 1,2

Helium 1s2 1,3

Lithium 1s2 2s1 1,3,5,6

Beryllium 1s2 2s2 1,3,5,7