Mr. Causey shows how easy it is to write ionic compound and covalent compound formulas. All you need is a periodic table, a list of polyatomic ions and some simple rules and you're ready to start writing formulas. http://www.yourCHEMcoach.com Share this Video: http://www.youtube.com/watch?v=16agvZ8K2eM Learn more and understand better with Mr. Causey's tutorials. Subscribe for more chemistry videos: http://bit.ly/1jeutVl Resources: Polyatomic Ion Cheat Sheet: http://bit.ly/14e2pbw Related Videos: Writing Ionic Formulas: http://www.youtube.com/watch?v=-T5W0ptk9SE Writing Covalent Formulas: http://www.youtube.com/watch?v=DwwNvNwGHjk Naming Compounds: http://www.youtube.com/watch?v=9XUsOLaz3zY Naming Ionic Compounds: http://www.youtube.com/watch?v=53T44hVKS_Q Naming Covalent Compounds: http://www.youtube.com/watch?v=7InLJxj7qDE Contact Me: mrcausey@mrcausey.com Follow Me: http://www.twitter.com/#!/mrcausey http://pinterest.com/mistercausey/ http://www.facebook.com/profile.php?id=814523544 In this lesson, we'll go through the formula anatomy, binary compounds, writing formulas, and ionic and covalent formulas. You will need a periodic table, unless you have it memorized. You will need a list of the major polyatomic ions. And if you get my list, you'll have a list of the metal cations and the numeric prefixes as well. You need to know oxidation numbers, polyatomic ions, the periodic table, covalent and ionic bonds, and the chemical names. It is very important to know these things. Especially, be familiar with the covalent and ionic bonds. So, a chemical formula, what is it? It's a symbolic representation of a chemical compound. For instance, potassium permanganate, its symbolic representation would be KMnO4. Let's take a look at formula anatomy. You need to make sure you understand how formulas are put together. Here's the formula for "calcium fluoride". The "Ca" and the "F", or the calcium and the fluorine, that's the elements. The small numbers below and to the right are called subscripts. Subscripts tell you how many atoms or ions are needed in that substance. There must be two fluorine ions in calcium fluoride. So, we put a two for the subscript. Since there is only one calcium ion, we don't write the one, similar to algebra. The number out in front is the coefficient and tells you how many formula units, molecules or moles are being used. Remember, most compounds are binary, meaning they have two parts. KCl or H2O. Notice that KCl is potassium and chlorine and H2O is hydrogen and oxygen.

• published: 05 Jun 2011
• views: 86896