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Formation of Ions

PostPosted: March 26th, 2011, 11:02 am
by Jessica
Formation of Positive Ions

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  1. First, remove all the valence electrons — all the electrons in the outermost energy level.

    EX. Write complete SN for Al. [Ne]3s[super]2[/super]3p[super]1[/super]

    Predict the most stable ion for Al by following rule #1. Al[super]+3[/super]

    Write the new complete SN for the ion you predicted. 1s[super]2[/super]2s[super]2[/super]2p[super]6[/super]

    To what noble gas is it isoelectronic? Ne

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  2. IF the 's' electrons are shielded by a 'd' or 'f' sublevel, remove just the 'p' electrons for the formation of one ion, and then all the valence electrons (rule #1) to form a second ion. An atom such as this NEVER loses only the s electrons.

    EX. Write shorthand SN for Sn. [Kr]5s[super]2[/super]4d[super]10[/super]5p[super]2[/super]

    Predict the most stable ions for Sn by following rule #2. Sn[super]+2[/super], Sn[super]+4[/super]

    Write the new shorthand SN for each ion you predicted. [Kr]5s[super]2[/super]4d[super]10[/super], [Kr]4d[super]10[/super]

    To what novel gas is each ion isoelectronic? pseudo Kr

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  3. 3. Remove 'd' or 'f' electrons to create a half-filled or empty 'd' or 'f' sublevel. This applies to transition and inner transition metals only. This ONLY occurs in addition to the removal of the valence electrons, so any 'd' or 'f' electrons removed must be ADDED to the number of valence electrons that were removed. You cannot remove only 'd' or 'f' electrons.

    EX. Write shorthand SN for Fe. [Ar]4s[super]2[/super]3d[super]6[/super]

    Predict a stable ion for Fe by following rule #1. Fe[super]+2[/super]

    Predict another stable ion for Fe b y following Rule #3. Fe[super]+3[/super]

    Write the new shorthand SN for each ion you predicted. [Ar]3d[super]6[/super], [Ar]3d[super]5[/super]



Formation of Negative Ions

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Since metals NEVER, NEVER, NEVER, gain electrons, the only elements that form anions are nonmetals, which are representative elements, so there are no 'd' or 'f' electrons to worry about.

Simply add electrons until the nonmetal is isoelectronic to a noble gas.

EX. Write the shorthand SN for Br. [Ar]4s[super]2[/super]3d[super]10[/super]4p[super]5[/super]

Predict the most stable ion for Br by following this rule. Br[super]-1[/super]

Write the new shorthand SN for the ion you predicted. [Ar]4s[super]2[/super]3d[super]10[/super]4p[super]6[/super]

To what nobel gas is the ion isoelectronic? Kr


EX. Write shorthand SN for N. 1s[super]2[/super]2s[super]2[/super]2p[super]3[/super]

Predict the most stable ion for by following this rule. N[super]-3[/super]

Write the new shorthand SN for the ion you predicted. 1s[super]2[/super]2s[super]2[/super]2p[super]6[/super]

To what noble gas is this ion isoelectronic? Ne