Ion Humour

Simple Ionic Compounds

What are ions? Atoms that lose an electron or gain an electron are called ions. Fluorine is a negative ion because it will gain an electron (-). All non-metallic ions gain electrons. Lithium is a positive ion because it will lose an electron All metallic ions lose electrons.

Oh…to be Noble... Valence electron = 1 Valence electron = 7 Fluorine Lithium Valence electron = 1 *To become stable lithium will lose one electron. Valence electron = 7 *To become stable fluorine will gain one electron.

+ Cations and Anions Positive ions are called cations. Negative ions are called anions. When cations and anions combine, they form an ionic compound... +

Energy in Bonding Ionic bonding results in a chemical change through the process of a reaction between two elements or substances. The mass, number and types of elements, and the energy involved must all remain constant in this process. WHAT GOES IN MUST COME OUT! Energy can be absorbed and/or released in several forms - heat, light, sound...

K+ + Cl- = KCl Formula Writing In order to have a stable compound, the number of electrons lost by one ion must equal the number of electrons gained by the other ion. K+ + Cl- = KCl

Formula Writing Continued…. In many cases, the number of electrons lost by one ion does not initially balance the number of electrons wanted by the other ion…or vice versa. Na+ + O2- = Na2O

Formula Writing Hints The “Criss-Cross” method is a fast shortcut to balancing. Take the charge of each ion and drop it over to the other symbol Reduce if necessary (lowest common denominator) Ca2+ + N3- = Ca3N2 The Table of Ions has all of the charges for ions… Always write the charges as the number, then the charge, ie. O 2-, not O -2 Remember that only metals with nonmetals will have charges to balance – do not do this with molecular compounds!

Naming Ionic Compounds 1. The cation (+ ion, metal) is first and keeps its regular metallic name. 2. The anion (- ion, non metal) is second. The anion name is the root; simple ions have the suffix (-ide). eg. Ca3N2 = calcium nitride Common anion names: sulfur = sulfide bromine = bromide nitrogen = nitride chlorine = chloride phosphorous = phosphide fluorine = fluoride

2. Mg + N = Mg2+ + N3- = Mg3N2

3. H + O = H+ + O2- = H2O

4. K + Cl = K+ + Cl- = KCl

5. K + O = K+ + O2- = K2O

6. Ca + O = Ca2+ + O2- = CaO