Periodic Table and Ion Formation Atoms gain and lose electrons to form bonds. The atoms become electrically charged particles called ions. Metals lose electrons and become positive ions (cations). Non-metals gain electrons and become negative ions (anions). See page 173 (c) McGraw Hill Ryerson 2007

Periodic Table and Ion Formation Atoms gain and lose electrons in an attempt to have the same number of valence electrons (electrons farthest from the nucleus) as the nearest noble gas in the periodic table. ~ ~ See page 173 (c) McGraw Hill Ryerson 2007

ATOMIC BONDING Forming Compounds See pages 176 - 177 (c) McGraw Hill Ryerson 2007

When two atoms get close together, their valence electrons interact. Forming Compounds When two atoms get close together, their valence electrons interact. See pages 176 - 177 (c) McGraw Hill Ryerson 2007

When two atoms get close together, their valence electrons interact. Forming Compounds When two atoms get close together, their valence electrons interact. If the valence electrons can combine to form a low-energy bond, a compound is formed. See pages 176 - 177 (c) McGraw Hill Ryerson 2007

When two atoms get close together, their valence electrons interact. Forming Compounds When two atoms get close together, their valence electrons interact. If the valence electrons can combine to form a low-energy bond, a compound is formed. Each atom in the compound attempts to have the stable number of valence electrons as the nearest noble gas. See pages 176 - 177 (c) McGraw Hill Ryerson 2007

When two atoms get close together, their valence electrons interact. Forming Compounds When two atoms get close together, their valence electrons interact. If the valence electrons can combine to form a low-energy bond, a compound is formed. Each atom in the compound attempts to have the stable number of valence electrons as the nearest noble gas. Metals may lose electrons and non-metals may gain electrons to form an IONIC BOND (IONIC BONDS ONLY OCCUR BETWEEN METALS AND NON-METALS) See pages 176 - 177 (c) McGraw Hill Ryerson 2007

Forming Compounds Ionic bonds form when electrons are transferred from positive ions to negative ions. See pages 176 - 177 (c) McGraw Hill Ryerson 2007

Forming Compounds (continued) Ionic bonds are formed between positive ions and negative ions. Generally, this is a metal (+) and a non-metal (-) ion. For example, lithium and oxygen form an ionic bond in the compound Li2O. + lithium oxygen Electrons are transferred from the positive ions to negative ions Li+ O2- Li+ lithium oxide, Li2O See pages 176 - 177 (c) McGraw Hill Ryerson 2007

EXAMPLE (c) McGraw Hill Ryerson 2007

Names and Formulas of Compounds Ionic compounds are made up of positive and negative ions. All of the positive and negative ions organize in a pattern. Negative-positive attract. Negative-negative and positive-positive repel. Salt, NaCl See pages 184 - 185 (c) McGraw Hill Ryerson 2007

Names and Formulas of Compounds Ionic compounds form from the inside out as solid crystals. Ionic compounds are like a solid stack of bricks. A salt shaker contains thousands of small pieces of NaCl. Salt, NaCl See pages 184 - 185 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound The name of an ionic compound = positive ion + negative ion-ide. For example, an ionic compound forms between magnesium and oxygen. The positive ion is the first part of the name, magnesium. The negative ion forms part of the ending of the name, ox(ygen). Add -ide to the end of the name to form magnesium oxide. Magnesium oxide is used as a drying agent. See pages 186 - 187 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound Ionic formulas are based on the ions of the atoms involved. Remember the naming principles above. For example, what is the name of Ca3N2? Ca, the positive ion, is calcium. N, the negative ion, is nitrogen. Drop the end of the anion and add -ide. Magnesium oxide is used as a drying agent. See pages 186 - 187 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound Ionic formulas are based on the ions of the atoms involved. Remember the naming principles above. For example, what is the name of Ca3N2? Ca, the positive ion, is calcium. N, the negative ion, is nitrogen. Drop the end of the anion and add -ide. Calcium nitride Magnesium oxide is used as a drying agent. See pages 186 - 187 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) Writing formulas for ionic compounds: In an ionic compound, the positive charges balance out the negative charges. ***ELECTRONS ARE TRANSFERRED FROM ATOMS. THEY CAN’T BE CREATED OR DESTROYED!**** Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) Writing formulas for ionic compounds: In an ionic compound, the positive charges balance out the negative charges. ***ELECTRONS ARE TRANSFERRED FROM ATOMS. THEY CAN’T BE CREATED OR DESTROYED!**** The ratio of positive:negative charges gives the proper formula. The ratio is always written in reduced form. Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) For example, what is the formula for magnesium phosphide? Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) For example, what is the formula for magnesium phosphide? magnesium is Mg2+ phosphorous is P3– Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) For example, what is the formula for magnesium phosphide? magnesium is Mg2+ phosphorous is P3– Lowest common multiple of 2 and 3 is 6 Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) For example, what is the formula for magnesium phosphide? magnesium is Mg2+ phosphorous is P3– Lowest common multiple of 2 and 3 is 6 3 Mg2+ ions and 2 P3– ions Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) For example, what is the formula for magnesium phosphide? magnesium is Mg2+ phosphorous is P3– Lowest common multiple of 2 and 3 is 6 3 Mg2+ ions and 2 P3– ions Mg3P2 Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) Try the formula for calcium oxide. Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007

The Chemical Name and Formula of an Ionic Compound (continued) Try the formula for calcium oxide. calcium is Ca2+ oxygen is O2– Lowest common multiple of 2 and 2 is 2 1 Ca2+ ion and 1 O2– ions CaO Calcium oxide, also known as “quicklime” was once produced by cooking limestone in ancient kilns. See page 188 (c) McGraw Hill Ryerson 2007