Chemistry - Easy methods to Prepare Covalent together with Ionic Chemical Formulas.

Writing chemical formulas is a necessary skill in the event that you are going to be successful in chemistry. Balancing equations, predicting reactions and calculating stoichiometric problems all rely in your ability to properly write a chemical formula. In the event that you make a mistake in the formula it'll affect the balancing and the mole ratios used to execute stoichiometric calculations. So take the time to learn how to properly write chemical formulas, you'll be glad you did.

What You Need certainly to Know...

1. How exactly to utilize the Periodic Table
2. How to make use of subscripts
3. How to find out ionic charges
4. Polyatomic ions
5. Metals with multiple charges
6. Greek and Latin numeric prefixes

The General Rule

Most compounds include two parts (binary) and are classified as ionic or covalent. The typical rule for naming and writing compounds is to place the more metallic element first followed closely by the less metallic element. RM257 Remember to make use of subscripts to show the amount of atoms or ions contained in the formula.

Writing Ionic Formulas

When writing the chemical formula for ionic compounds place the cation first, then a anion and check to see that the charges balance to zero. If the charges aren't balanced, you need to increase the amount of cations and anions until the algebraic sum of the charges is zero.

• If the charges are (2+) and (3-) the sum is (1-) and is not balanced. But the lowest common multiple of 2 and 3 is 6. So using subscripts increase the amount of cations by 3 and the amount of anions by 2.


• Thus (2+) times 3 is (6+) and (3-) times 2 is (6-) and (6+) + (6-) is zero. Balanced.

If the cation has multiple charges, the correct charge is indicated by way of a Roman numeral placed following the cation's name. Remember to treat polyatomic ions as complete unit, do not separate them.

EXAMPLE #1: calcium chloride is CaCl2 (calcium 2+) (chlorine 1-) increase the chlorine to two.

EXAMPLE #2: lithium nitrate is LiNO3 (lithium 1+) (nitrate 1-) balanced.

EXAMPLE #3: iron (II) sulfate is FeSO4

Writing Molecular Formulas (covalent)

When writing the chemical formula for covalent compounds place the less electronegative element first followed closely by the more electronegative element and use subscripts to indicate the amount of atoms present. Remember that prefixes are employed only with covalent compounds.

EXAMPLE #1: carbon dioxide is CO2 (1 C) (2 O)

EXAMPLE #2: phosphorous pentachloride is PCl5 (1 P) (5 Cl)

Don't Forget to Practice

Really, that's all there's to writing chemical formulas. Now you need to rehearse, practice and practice some more. Although chemical formulas aren't all that hard, you need to rehearse in the event that you are going to be worthwhile at it.