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 Cation: A positively charged ion Anion: A negatively 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

Properties of Ionic Compounds  Formed by ionic bonds  Electrons are either gained or lost  Have a regular repeating pattern called a crystal lattice  Formed between metals with nonmetals; cations with anions  High Melting point and Boiling Point  Conductors of electricity Strong bonds; stronger than covalent bonds

Lewis Structures  Ionic – show the transfer of electrons

Ionic Bond y an 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:

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. Ionic Nomenclature continued…

EXAMPLE:  Calcium Nitrate Ca +2 NO 3 -1 Ca +2 NO 3 -1 Ca 1 (NO 3 ) 2 Ca 1 (NO 3 ) 2 Ca (NO 3 ) 2 Ca (NO 3 ) 2 1(+2) + 2(-1)= 0 1(+2) + 2(-1)= 0 Cross the exponents only! not the + or - Do NOT show 1 in the final formula Polyatomic ion NO 3 goes in parentheses This is your final formula! Check for the overall charge to equal zero

z potassium chloride z magnesium nitrate z copper(II) chloride y K + Cl  y Mg 2+ NO 3  y Cu 2+ Cl   KCl  Mg(NO 3 ) 2  CuCl 2 Ionic Nomenclature Ionic Nomenclature

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.

z NaBr z Na 2 CO 3 z FeCl 3 y sodium bromide y sodium carbonate y iron(III) chloride 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?

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) AgI