Chemistry : The way to Compose Covalent and also Ionic Chemical Formulas.

 Writing chemical formulas is an essential 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. If you make a mistake in the formula it'll affect the balancing and the mole ratios used to do stoichiometric calculations. So take the time to learn how to properly write chemical formulas, you'll be glad you did.

What You Need to Know...

1. How exactly to utilize the Periodic Table
2. How to use 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 consist of two parts (binary) and are classified as ionic or covalent. The typical rule for naming and writing compounds is to put the more metallic element first accompanied by the less metallic element. Remember to use subscripts showing the number 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 note that the charges balance to zero. If the charges aren't balanced, you must increase the number of cations and anions before 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 number of cations by 3 and the number 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 after the cation's name. CAS 174063-87-7 Remember to take care of polyatomic ions as complete unit, don't separate them.

EXAMPLE #1: calcium chloride is CaCl2 (calcium 2+) (chlorine 1-) raise 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 accompanied by the more electronegative element and use subscripts to indicate the number of atoms present. Understand that prefixes are used only with covalent compounds.

EXAMPLE #1: co2 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 apply, practice and practice some more. Although chemical formulas aren't all that hard, you will need to apply in the event that you are going to be a bit of good at it.