Atomic Size - the elements move from left to right across a...

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Atomic Size (Atomic Radius) The atomic size of an atom, also called the atomic radius, refers to the distance between an atom's nucleus and its valence electrons. Remember, the closer an electron is to the nucleus, the lower its energy and the more tightly it is held. Moving Across a Period Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons. True, electrons are also added as
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Unformatted text preview: the elements move from left to right across a period, but these electrons reside in the same energy shell and do not offer increased shielding. Moving Down a Group The atomic radius increases moving down a group. Once again protons are added moving down a group, but so are new energy shells of electrons. The new energy shells provide shielding, allowing the valence electrons to experience only a minimal amount of the protons' positive charge....
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This note was uploaded on 11/14/2011 for the course CHEM ch 101 taught by Professor - during the Fall '10 term at Montgomery.

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