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Ionic/Covalent Compound Names and Formulas. +1. +2. +3 -5. + 4. -3 +5. -2. -1. 0. We want to bond Magnesium and Oxygen. +1. +2. +3 -5. + 4. -3 +5. -2. -1. 0. Step 1: What are the oxidation states?. Use the periodic table trick:. Mg +2. O -2. Step 2: Are charges balanced?.
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+1 +2 +3 -5 +4 -3 +5 -2 -1 0 We want to bond Magnesium and Oxygen
+1 +2 +3 -5 +4 -3 +5 -2 -1 0 Step 1: What are the oxidation states? • Use the periodic table trick:
Mg+2 O-2 Step 2: Are charges balanced? • To be balanced, the net (overall) charge MUST be ZERO. How many positive charges are there? How many negative charges are there?
Mg+2 O-2 Step 3: Figure out your formula What is +2 + -2? Is the overall charge zero? So what is your formula? MgO
Mg+2 O-2 Step 4: What is your compound called? • The cation ALWAYS comes first and keeps its name the way it is written. • Magnesium • The anion ALWAYS comes second and the end comes off and is replaced with -ide • Oxygen gets changed to oxide Magnesium Oxide
+1 +2 +3 -5 +4 -3 +5 -2 -1 0 Let’s Practice • Let’s combine Magnesium and Chlorine. • Step 1: What are the ox. states?
Cl-1 Mg+2 • Step 2: Are the charges balanced? • Is the overall charge ZERO? • NO! We have too many positive charges. How many positive charges are there? How many negative charges are there?
Cl-1 Cl-1 Mg+2 What do we do now? • How can we make the charges balance? -2 -1 +2
Cl-1 Cl-1 Mg+2 What’s the formula? • What would the formula for this ionic compound be? MgCl2 What would we call it? Magnesium chloride
Try the following: • With your neighbor, make a balanced formula and the correct names for these ionic compounds: Na + Cl Al + Cl Mg + S K + O Na + O Ca + F Al + O (This one’s hard!)
Remember this…. • A covalent compound forms between two or more nonmetals so we don’t have to worry about ion formation or oxidation states.
A simple set of rules can be used to name them: • Step 1: Name the elements in the order they appear in the formula. For example, CO2 would be named carbon oxygen. Or is it?
What about the subscripts? • Step 2: Use prefixes to indicate how many elements there are of each type. This rule may be modified to improve how the name sounds.
What type of ending do I use? • Step 3: Use the ending –ide for the second element listed in the formula.
So this means that ……… • CO2 would be named carbon dioxide.
How would I write the formula if given the name? • Use the symbols of the elements with their corresponding prefix numbers. • Dinitrogen Trioxide would be __________.