IONIC BONDING

What is an ion? An ion: an atom or bonded group of atoms with a positive or negative charge Cation: A positively charged ion Anion: A negatively charged ion

Ionic Compound Composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal An ionic bond is the electrostatic force that holds oppositely charged particles together in an ionic compound.

Properties of Ionic Compounds Formed by ionic bonds Electrons are either gained or lost Have a regular repeating pattern called a crystal lattice Elements are generally far apart from each other (metals with nonmetals; cations with anions) High Melting point and Boiling Point Conductors of electricity when mixed with water Formation of these is exothermic Strong bonds; stronger than covalent bonds

Ionic Bonds continued: Ionic Bonding - Crystal Lattice yThe strong attraction of positive ions and negative ions in an ionic compound results in a crystal lattice. y A crystal lattice is a three dimensional geometric arrangement of particles. y In a crystal lattice, each + ion is surrounded by - ions and each – ion is surrounded by + ions. Ionic crystals vary in shape due to the sizes and relative numbers of the ions bonded.

Common Ion Charges / C. Ionic Nomenclature

B. Lewis Structures Ionic – show transfer of e -

Ionic Bond yan electron is simply transferred to another atom. By doing so, each atom is able to have a stable valence shell. It is called an ionic bond because the atoms become ions, a charged atom that has either lost an electron (positive charge) or has gained an electron (negative charge). Below is an animation of ionic bonding:

C. Ionic Nomenclature Ionic Formulas Write each ion, cation first. Don’t show charges in the final formula. Overall charge must equal zero. –If charges cancel, just write symbols. –If not, use subscripts to balance charges.

Ionic Formulas Use parentheses to show more than one polyatomic ion. Stock System – –Roman numerals indicate the ion’s charge used when the ion has more than one oxidation state. C. Ionic Nomenclature

zpotassium chloride zmagnesium nitrate zcopper(II) chloride  K + Cl   Mg 2+ NO 3   Cu 2+ Cl   KCl  Mg(NO 3 ) 2  CuCl 2 C. Ionic Nomenclature

Ionic Names Write the names of both ions, cation first. Change ending of monatomic ions to -ide. Polyatomic ions have special names. Stock System - Use Roman numerals to show the ion’s charge if more than one is possible. Overall charge must equal zero.

zNaBr zNa 2 CO 3 zFeCl 3 ysodium bromide ysodium carbonate yiron(III) chloride C. Ionic Nomenclature

Consider the following: –Does it contain a polyatomic ion? -ide, 2 elements  no -ate, -ite, 3+ elements  yes –Does it contain a Roman numeral? Check the table for metals not in Groups 1 or 2.

Assignment Provide the ionic compound formula or the name 1.Potassium fluoride 2.Magnesium phosphide 3.Aluminum iodide 4.Nickel II Oxide 5.Lead IV Oxide 6.K 2 CO 3 7.Pb(NO 3 ) 2 8.Ca 3 N 2 9.Zn(CN) 2 10.AgI