B. Lewis Structures zIonic – show transfer of e -
Things to know about Ionic z Ionic compounds are made up of? z The electrons are being? z What is written first? z Opposite charges will?
Oxidation Number z Oxidation number is the number of electrons an atom gains or loses when bonding. z This can be determined by understanding the valence electrons, and how atoms become stable. z An atom is stable when it has a complete outer energy level, typically eight valence electrons.
Look at Boron in it’s normal state Not stable! – NO OCTET! How would this atom become stable? Gain 5 or lose 3? And the winner is….. Oxidation Number
How to write Ionic Formulas Ionic Formulas zOverall net charge must equal zero. zS.O.C.S zSymbols -> Oxidation # -> Crisscross -> Simplify zDO NOT show charges in the final formula.
Writing Formula Practice zPotassium Chloride K + S K2SK2S zBeryllium Sulfide Be +2 S BeS = Reduce
Ionic Nomenclature How to Name an Ionic Compound zWrite the name of the Cation (Metal) first. It comes straight off the periodic table. zChange ending of the Anion (Nonmetal) to end in -ide.
Naming Practice zAl 2 O 3 zAluminum Oxide zCaS zCalcium Sulfide
Polyatomic Ions z When you have a compound that has more than 2 elements, you must look at a Polyatomic Chart for help. z When writing these formulas, keep these ions in parentheses. z These ions will also have different endings (-ate) (-ite) zUse the same SOCS method for writing formulas.
Writing a Formula z You need to determine if a Polyatomic Ion is present! How? z Look at the suffix of the name. z (-ATE) or (-ITE) indicates Polyatomic Ion z What are some exceptions??? z What if the ending is (-IDE)? z (-IDE) usually indicates periodic table element. Note exceptions!
Writing Polyatomics z Potassium Nitrate z KNO 3 z Aluminum Sulfide z Al 2 S 3 z Barium Phosphite z Ba 3 (PO 3 ) 2
Naming Polyatomics z Look for more than two elements. That’s means a Polyatomic ion is present. z Match up the polyatomic ion from the chart and copy the name and ending straight from the chart.
Practice w/ Polyatomics z CaSO 4 zCalcium Sulfate zGa(IO 3 ) 3 zGallium Iodate
Writing formulas with Transition Metals z When a Transition metal is involved, you must identify which ion is bonding. z These ions have different oxidation numbers. z Look for the Roman Numeral in the name when writing the formula. z The Roman numeral is the oxidation number of the transition metal.
Practice Writing Trans z Copper (II) Fluoride z CuF 2 z Nickel (IV) Oxide z NiO 2 (Simplified formula)
Naming Transitions zWhen naming the compound, you must balance the total charge, (It must be zero!) zLook at the Anion and Determine the total charge. (Multiply Oxidation # by subscript) zLook at the Cation. Remembering that the sum of the ionic compound must equal zero, zDetermine the positive charge, and it will be the correct roman numeral.
Practice Naming Trans z Au 2 S z Gold(I) Sulfide z ZnO z Zinc (II) Oxide z FeN z Iron(III) Nitride