Today’s Do Now 10/14/2014 Draw the Lewis Structure of Chlorine. Draw the Lewis Structure of Sodium. If sodium and chlorine were to form a bond, what type of bond would form? How do you know? What is the definition of electronegativity?

Ionic Bonds It’s getting serious

By the end of the class period today I will be able to… draw Lewis Dot Diagrams representing the transfer of electrons in ionic bonds. write the chemical formulas for ionic compounds including polyatomic ions utilizing the criss-cross method.

Sodium Chloride = NaCl For example… “-ide” means it’s just a single element from the PT (but there can be more than one of them)

It’s not always simple though… Calcium Chloride = CaCl

Steps to Writing Ionic Formulas 1. Write positive ion first, then the negative 2. Determine the charge on each ion 3. Crisis cross and reduce Subscripts: Numbers below the element that indicate the number of that element.

Let’s try one together: Write the chemical formula for Lithium Oxide.

You try: Write the chemical formula for Magnesium Bromide.

You try: Write the Chemical formula for Sodium Sulfide.

You Try Write the chemical formula for Magnesium Oxide.

Sometimes there is something called a polyatomic ion included. What is the formula for Calcium Chlorate? Calcium = Ca Chlorate? Endings that are not “-ide” mean you have a polyatomic ion.

Chlorate = ClO3 Polyatomic Ions A group of atoms that are bonded together and collectively act as an anion. Chlorate = ClO3

Polyatomic Ions are found on the STAAR Ref sheet:

Writing Formulas with Polyatomic Ions Steps to writing an ionic compound: 1. Write the formulas for the ions 2. Criss cross and reduce if necessary. 3. If a subscript is written on a polyatomic ion, polyatomic ion is placed in parentheses, and when the subscript is one, it is not written.

Let’s do one together… Write the formula for Calcium Nitrite.

You try… Write the formula for Potassium Nitrate.

You try… Write the formula for Sodium Sulfate.

You try… Write the formula for Magnesium Phosphate.

What if there is a Transition Metal?? The oxidation number of the transition metal will be written as a roman numeral in parentheses. Criss-Cross! Copper (II) chloride Copper (III) chloride

Example: Iron (III) Sulfide

Manganese (IV) Fluoride Example: Manganese (IV) Fluoride

Write the formula for… Lead (II) Iodide

Lead(II) Iodide PbI2

Example: Lithium Carbonate

Lithium Carbonate Li2CO3

Example: Iron (III) Carbonate

Iron (III) Carbonate Fe2(CO3)3

Independent Practice Strontium phosphide Beryllium sulfide Copper (III) sulfite Titanium (II) oxide Ammonium fluoride Sodium nitrite Nickel (II) sulfate Chromium (II) nitride