How To Name Chemical Formulas Supplemental to Chapter 20

Rules for Naming Binary Compounds Binary Compounds are ionic bonds between one metal (+) and one nonmetal (-). When you name binary ionic compounds, you always mention the cation ( + ion) first (usually the metal). When you name the second ion (the – anion), you will change the ending to “ide”

Common Binary Anions Oxygen oxide Phosphorusphosphide Nitrogennitride Sulfursulfide Chlorinechloride

Name These Binary Compounds RbCl = NaF = CuO = AlN= K 2 S = NaCl =

Name These Binary Compounds RbCl = Rubidium Chloride NaF = Sodium Fluoride CuO = Copper Oxide AlN= Aluminum Nitride K 2 S = Potassium Sulfide NaCl = Sodium Chloride

Polyatomic Ions Polyatomic ions are a group of ions (2+ elements) that are covalently bonded together. 1)You would say the first element as is. 2)You would then say the rest of the bonded polyatomic ions after the first element, using their specific endings.

Polyatomic Ion Endings Ammonium NH 4 Acetate C 2 H 3 O 2 Chlorate ClO 3 Hydroxide OH Nitrate NO 3 CarbonateCO 3 SulfiteSO 3 SulfateSO 4 PhosphatePO 4 Peroxide O 2

Oxygen vs Peroxide Normally an Oxygen molecule by itself is O 2. However, if it is in a polyatomic bond, the O 2 becomes peroxide. O 2 = oxygen, Na 2 O 2 = sodium peroxide Remember the difference between the chemical formulas for water and hydrogen peroxide: water = H 2 O; hydrogen peroxide = H 2 O 2

Rules for Polyatomic Ions You have to memorize the chart, including SO 3 (Sulfite) and O 2 (Peroxide). Remember, O 2 is peroxide only when used as a polyatomic ion. Otherwise it is oxygen (oxide.)

Naming Polyatomic Ions HSO 4 - NaNO 3 - Ba(OH) 2 - KNO 3 - CaCO 3 - CuSO 3 – CaSO 4 – (notice the different endings of the last two polyatomic ions.)

Naming Polyatomic Ions HSO 4 - Hydrogen Sulfate NaNO 3 - Sodium Nitrate Ba(OH) 2 - Barium hydroxide KNO 3 - potassium nitrate CaCO 3 - calcium carbonate CuSO 3 – copper sulfite CaSO 4 – calcium sulfate H2O 2 – hydrogen peroxide

Prefixes for Covalent Compounds The prefixes indicate how many atoms of each element are in a binary covalent compound. These occur when 2 nonmetals covalently bond.

Prefixes for Covalent Compounds Mono = 1 Di = 2 Tri = 3 Tetra = 4 Penta = 5 Hexa = 6 Hepta = 7 Octa = 8

How to Say Covalent Compounds P 2 O 5 - this is named diphosphorus pentoxide, because there are two phosphorus atoms and five oxygen atoms. CO - this is carbon monoxide (you need the "mono-" because there's only one oxygen atom). CF 4 - this is carbon tetrafluoride

The Covalent Bond of Water Water is a covalent bond (2 Hydrogen atoms share the 6 Oxygen valence electrons of one atom) H 2 O Dihydrogen monoxide This is a chemical formula you should know.

Naming Covalent Bonds Rules Use specific prefixes to indicate the total number of atoms involved. Don’t write 2 vowels together unless it is dioxide. (CO 2 = carbon dioxide) If there is only one atom for both elements, you don’t write the “mono” for the first element, but you do for the 2 nd element. Examples: CO = carbon monoxide