Chapter 4 Section 3 Compound names and formulas

Naming Ionic Compounds  Binary compounds (Compounds with just two elements) Na 2 S 1. Name the first element - Sodium 2. Name the root of the second element – “Sulf” 2. Name the root of the second element – “Sulf” 3. Add the ending “ide” to the root Sodium Sulfide Sodium Sulfide ALL binary compounds will end with “ide”. *There is an exception – compounds with ammonium can also end in “ide”….. Ammonium Bromide

Naming ionic compounds  The first name is the name of the cation  Example: CaCl 2 has first name calcium  The last name has the name of the anion. (Anion names always end in “ide” unless they are from your polyatomic ion chart.)  Example: CaCl 2 has last name chloride, so CaCl 2 is calcium chloride so CaCl 2 is calcium chloride

Name these ionic compounds  1. BaF 2  2. K 2 Se  3. CaS  4. AlF 3  5. LiH

Inonic Compounds Some common Cations Name and Symbol Ion charge Name and Symbol Ion charge Cesium ion, Cs+ 1 Lithium ion, Li+ 1 Potassium ion, K+ 1 Rubidium ion, Rb+ 1 Sodium ion, Na+ 1 Barium ion, Ba+ 2 Beryllium ion, Be+ 2 Calcium ion, Ca+ 2 Magnesium ion, Mg+ 2 Strontium ion, Sr+ 2 Aluminum ion, Al+ 3 Some common Anions Name and Symbol Ion charge Name and Symbol Ion charge Fluorine, F FluorIDE - 1 Chlorine, Cl ChlorIDE - 1 Bromine, Br BromIDE - 1 Iodine, I IodIDE - 1 Oxygen, O OxIDE - 2 Sulfur, S SulfIDE - 2 Nitrogen, N NitrIDE - 3

Some cation names must show their charge TTTTransition metals may form several cations each with a different charge. TTTThese cations must have a Roman Numeral in parenthesis. The Roman Numeral shows the cation’s charge.

Formulas with transition metals………..  EXAMPLE: Fe 2 O 3 - Look first at the element combined with the transition. Oxygen forms a - 2 ion, if there are 3 atoms each with a -2 charge there is a total charge of -6..So if Iron has 2 atoms, the total charge must equal +6. Then this is made of Fe +3 ions (+3 X 2 = +6), so it is named Iron (III) Oxide;  FeO is made of Fe +2 ions so it is named Iron (II) Oxide.

What are the charges on ions?

Ionic compounds that contain more than 2 elements  Compounds containing polyatomic ions have charges listed on your polyatomic ion chart. *Notice that all “ate” and “ite” suffixes are compounds that have oxygen in them.

Writing formulas for Ionic Compounds  What is the chemical formula for aluminum fluoride? 1.List the symbols for each ion Al +3 F -1 2.Write the symbols for the ions with the cation first…. Al +3 F -1 3.Find the least common multiple of the ions charges, so that the positive and negative charges will balance…… need total of 3 negative charges to balance with Al’s 3 positive charges. 4.Write the chemical formula, indicating with subscripts how many of each ion are needed to make a neutral compound…… AlF 3 leave the charges off

Practice writing ionic formulas  1. Ca 2+ combined with F -  CaF 2  2. Co 3+ combined with PO 4 3-  CoPO 4  3. Ni 2+ combined with OH -  Ni(OH) 2

More practice 1111. calcium combined with oxygen Ca2+ O2-  C aO 2222. potassium combined with oxalate K1+ C C2O42-  K 2C2O4 3333. barium hydrogen sulfate Ba2+ HSO41-  B a(HSO4)2

Practice makes perfect only if you practice perfect!  Write formulas for:  Calcium sulfide  Ca 2+ S 2-  CaS  Potassium sulfide  K +1 S 2-  K 2 S

Practice makes perfect only if you practice perfect! WWWWrite formulas for: CCCCalcium sulfite  C a2+ SO32- aSO3 PPPPotassium sulfate  K +1 SO42- 2SO4

Practice makes perfect only if you practice perfect! WWWWrite formulas for: GGGGallium oxide  G a3+ O2- a2O3 AAAAmmonium Phosphite  N H4+1 PO33-  ( NH4) 3PO3

Some Transition Metal Cations  Ion name Symbol Copper (I) Cu +1 Copper (II) Cu +2 Iron (II) Fe +2 Iron (III) Fe +3 Nickel (II) Ni +2 Nickel (III) Ni +3 Lead (II) Pb +2 Lead (IV) Pb +4 Mercury (I) Hg +1 Mercury (II) Hg +2 Gold ((I) Au +1 Gold (III) Au +3  Ion name Symbol Chromium (II)Cr +2 Chromium (III)Cr +3 Tin (II) Sn +2 Tin (IV) Sn +4 Titanium (II)Ti +2 Titanium (III)Ti +3 Titanium (IV)Ti +4 Manganese (II)Mn +2 Manganese (III)Mn +3 Manganese (IV)Mn +4 Manganese (VI)Mn + 6 Manganese (VII)Mn + 7

Math Skills….. Write formulas for the following ionic compounds: 1.Lithium oxide 2.Beryllium chloride 3.Titanium (III) nitride 4.Cobalt (III) hydroxide LiO 2 BeCl 2 TiN Co(OH) 3

Naming Covalent compounds  Covalent compounds are named using different rules than those used to name ionic compounds  Numerical prefixes are used to name covalent compounds of two elements Number of atoms Prefix 1 Mono 2 Di- 3 Tri- 4 Tetra- 5 Penta- 6 Hexa- 7 Hepta- 8 Octa- 9 Nona- 10 Deca- Dinitrogen tetroxide N 2 O 4 has 2 Nitrogen atoms and 4 Oxygen atoms.

What about covalent compounds?  Many covalent compounds are named with prefixes.  Examples:  CO 2  SO 2  H 2 O 5

Many covalent compounds are hydrocarbons with special names  Examples:  CH 4  C 2 H 6  C 2 H 4  C 2 H 2

Naming non-binary compounds (polyatomics)  Use the first element name  Add the polyatomic name ****A hint – any time you see a compound with three or more elements it is a good sign that it may include a polyatomic*** CHECK YOUR LIST Example: NaNO 3 -

Name these…..  Mg(NO 3 ) 2  Pb(OH) 2  CuCO 3  K 3 PO 4  NH 4 Cl

Chemical Formulas for Covalent Compounds  A compound’s simplest formula as its empirical formula  Different compounds can have the same empirical formula  Molecular formulas are determined from empirical formulas

Check your understanding  ASSIGNMENTS Writing Binary formulas Naming Binary Compounds (Ionic) Naming Binary Compounds (Covalent) Formulas with Polyatomic Ions Naming of Non-Binary Compounds Naming Compounds (Mixed)

Compound Names and Formulas  Empirical formula – the simplest chemical formula of a compound that tells the smallest whole-number ratio of atoms in the compound  Molecular formula – a chemical formula that reports the actual numbers of atoms in one molecule of a compound 4.3