Ionic Bonding ule_viewer.php?mid=55

IONICCOVALENT High melting pointLow melting point Brittle solids at room temp.Often liquids or gases at room temp Combination of metal and nonmetal Combination of 2 nonmetals Smallest unit: Formula unit (ratio of ions) Smallest unit: Molecule Named without prefixesNamed using prefixes 2 elements always have the same structure 2 elements can often bond in several ways Conduct when melted or dissolved Not conductive at all

Ions and Ionic Bonds Formed from the gain or loss of electrons to produce stable ions The ions are opposite in charge and attract Cation- element loses electrons to become positive- metals Anion- element gains electrons to become negative- nonmetals Cation and anion interact to form ionic bond Polyatomic ions- group of elements with a charge- look on the back of your periodic table

Ionic bonding Wikipedia provided the picture

Review of ion formation Atoms are stable when they have 8 valence electrons Metals will lose 1-3 electrons (sometimes more) because this requires less energy than gaining 5-8 electrons Nonmetals will gain 1-3 electrons because this requires less energy than losing 5-8 electrons Nonmetals like B and C with 3 and 4 valence electrons do not form ionic bonds- they just share electrons- form covalent bonds

Naming of ionic compounds The cation is always named first. Cations can be metals or polyatomic ions For metals that have only one possible charge the name of the metal is used. Examples are Group I metals (charge 1+), Group II metals (charge 2+), Aluminium (charge 3+), Zinc (charge 2+), Silver (charge 1+) For metals that can have more than one charge the name of the metal is succeeded by the charge in capital Roman numerals in brackets OR by using the suffix -ous for the lowest charge and -ic for the highest charge and sometimes with the Latinized name for the metal

Examples of naming for multiple charges ElementCationPreferred Name Other Name copperCu + copper (I)cuprous Cu 2+ copper (II)cupric ironFe 2+ Iron (II)Ferrous Fe 3+ Iron (III)Ferric Lead Pb 2+ Lead (II)Plumbous Pb 4+ Lead (IV)plumbic Mercury Hg 2 2+ Mercury (I)Mercurous Hg 2+ Mercury (II)Mercuric Tin Sn 2+ Tin (II)Stannous Sn 4+ Tin (IV)Stannic

How do you know if you use Roman numerals? Do not use Roman Numerals for groups 1A, 2A, Al, Zn, Ag Use Roman Numerals for transition metals, Sn, Pb What Roman Numeral do I use? Find the charge of the cation by working backwards All compounds must be neutral- they must have a charge of zero. What if the cation is a polyatomic? Use the name from the polyatomic ion sheet

How do you name the anion? Use the root name plus –ide S 2- Sulfide What if it’s a polyatomic ion? Use the name of the polyatomic ion from the sheet you have

Examples of ionic naming NaI Sodium iodide KBrPotassium bromide MgOMagnesium oxide KO 2 Potassium oxide