Periodic_trends

In the world of the atom the electrons and nucleus

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Unformatted text preview: of states. In the world of the atom the electrons and nucleus interact to make the most stable electron arrangement possible. This is called the electron configuration of an atom. ) There are 7 main energy (quantum) levels around the nucleus of an atom numbered 1 to 7 ) Within each quantum level there are anywhere from 1 to 4 sublevels labelled s, p, d and f ) Within each sublevel there could be 1, 3, 5 or 7 orbitals ) Within each orbital you will find 0, 1, or 2 electrons Energy Quantum energy level Sublevel - spin electron orbital + spin electron Three rules govern the electron configuration of an atom: ) the Aufbau principle Electrons enter the orbitals of lowest energy(ground state) first. ) The Pauli Exclusion Principle Any orbital may contain at most 2 electrons, but they must be of opposite spin ) Hund's Rule When electrons enter orbitals of equal energy, one electron will enter each orbita; until all orbitals Writing Electron Configurations Order of Filling Sublevels with Electrons the energy sublevels are filled in a specific order that is shown by the arrow diagram seen below: or you can use the block organization of the periodic table to write electron configurations H Li 1 3 1s 1 Na 11 K 19 Rb 37 Cs 55 Fr 87 1s22s 1 1s22s22p63s 1 1s He 2 Ne 2 10 Ar 18 1s 2s 2p 2 2 Kr 36 Xe 6 54 Rn 86 1s22s22p63s 3p Elements can be classified into 4 categories based on their electron configuration. ) The Noble Gases (inert...
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This note was uploaded on 07/06/2011 for the course SCH 4U taught by Professor White during the Spring '10 term at Beacon FL.

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