High school11 min

Writing an electron configuration

Klechkowski, Pauli, Hund: write the configuration of an atom and then of its ion, count valence electrons, and stop getting copper and iron(II) wrong.

The essentials

1

Reading the notation

In 2p42p^4: 22 is the shell (nn), p the subshell, 44 the number of electrons. Capacities to know: s →2\to 2, p →6\to 6, d →10\to 10 (one, three and five orbitals of 22 electrons).
2

The Klechkowski (Madelung) rule

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3

Pauli and Hund

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4

Shorthand notation and two exceptions

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5

Valence electrons and ions

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