Octet Rule

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Octet Rule

• The tendency of atoms to rearrange themselves
  during chemical reactions so that each atom has a
  stable octet.
• All atoms want to be noble 8 valence electrons

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IONS

• Ions Electrically charged atoms, become charged
  by gaining or losing electrons.
• Cations Positive ions, lose electrons,
  typically metals
• Anions Negative ions, gain electrons, typically
  nonmetals

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Polyatomic ions

• A group of atoms chemically combined that carry a
  charge

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Ionic Compounds

• A compound formed from a metal and a nonmetal.
• Compounds have no net charge
• When ionic compounds are formed, metal atoms
  transfer electrons to nonmetal atoms

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Naming Ionic compounds

• Binary compound Compounds containing 2 types of
  atoms - metal and nonmetal.
• NAMING
• Cation or metal is given the name of the metal
• The name of the anion or nonmetal is altered
  by adding the suffix ide to the root word.
• Ex) CaCl2 Calcium Chloride
• (Metal) (Nonmetal)
• (cation) (anion)

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II. Ionic compounds that include polyatomic
ions

• Use the name of the polyatomic ion when it is
  part of an ionic compound (cation 1st, anion 2nd)
• Ex) Mg(OH)2 Magnesium Hydroxide
• Li2SO4 Lithium Sulfate

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III. Ionic compounds with multiple charges
(D-block metals)

• Note D block metal can form cations with more
  than 1 charge.
• The name of the metal ion is the name of the
  metal followed by a roman numeral in parenthesis.
• Ex) Ion Written Named
• Fe2 Fe(II)
  Iron 2
• Fe3 Fe(III) Iron 3

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Example

• FeCl2 Iron(II)chloride
• FeCl3 Iron(III)chloride
• CuO Copper(II)oxide
• Cu2O Copper(I)Oxide
• CuSO4 Copper(II)sulfate

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Molecular (covalent) compounds

• Molecular compounds - Compounds made up of
  molecules not ions.
• In molecular compounds electrons are shared to
  obtain an octet.
• Molecular compounds contain covalent bonds.
• Covalent bonding - Bonding between atoms in which
  the electrons are shared.

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Naming molecular compounds

• 1. Element of apparent positive charge comes
  first in the compound. (leftmost in the periodic
  table)
• 2. Two elements can form more than one compound,
  therefore prefixes are used to distinguish
  compounds.
• Prefixes 1 mono 2 di 3 - tri 4 - tetra
• 5 - penta 6 - hexa
• 3. The prefix mono is not used for the first
  element in a compound.
• 4. ide ending is used for molecular compounds

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Examples

• N2O Dinitrogen Monoxide
• N2O3 Dinitrogen Trioxide
• NO2 Nitrogen Dioxide
• CCl4 Carbon tetrachloride
• CO Carbon Monoxide
• S2O6 Disulfur Hexafluoride