Unit Five Nomenclature

Nomenclature Introduction  Ionic bonds are formed when electrons are transferred between one metal and one non-metal element. Covalent bonds are formed when electrons are shared between two non-metal elements. Because each bond is different, scientists must have a specific way to name ionic compounds, and a different way to name covalent or metallic compounds. Today we will go through some examples of how we name ionic and covalent compounds and practice what we learn from the sample problems.

Review  1.) Ions that have a positive charge are called  2.) Ions that have a negative charge are called  3.) Metals tend to electrons to become  4.) Non-metals tend to electrons to become

Determine which naming system to use FIRST  A. Stock System (Ionic Bonds)  Molecules involved are metals and non metals.  B. Molecular System (Covalent Bonds)  Molecules involved are only nonmetals.

A. Stock System (Ionic Bonds) If the compound is Binary – contains only 2 types of atoms.  Ionic Compounds  Write the full name of the 1 st element.  Write the name of the 2 nd element, but change the ending to “ide”  Put the two together and you have the correct name for the compound. Example: NaF- Sodium Fluoride

Example One Write the proper name for NaCl.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first:  Step 3: Write the name of the element that is the anion second but change the ending to “ide”  Step 4: Put step 2 and step 3 together and you have the correct name for the compound.

Example Two Write the proper name for CaS.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first:  Step 3: Write the name of the element that is the anion second but change the ending to “ide”  Step 4: Put step 2 and step 3 together and you have the correct name for the compound.

Example Three Write the proper name for LiF.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first:  Step 3: Write the name of the element that is the anion second but change the ending to “ide”  Step 4: Put step 2 and step 3 together and you have the correct name for the compound.

Example Four Write the proper name for BeO.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first:  Step 3: Write the name of the element that is the anion second but change the ending to “ide”  Step 4: Put step 2 and step 3 together and you have the correct name for the compound.

Review Stock System (Ionic Bonds) 1.AgCl 2.NaO 3.PbO 4.CoCl 2 5.SnF 2  Look over the flowchart to review the steps of forming an ionic bond. Use the notes and the flowchart to name the following ionic compounds. 6. Cr 2 O 3 7.CuO 8.K 3 N 9.NiS 10. SrBr 2

Review Stock System (Ionic Bonds) 11.MgI 2 12.BaCl 2 13.BaS 14.VP 15.HgS  Look over the flowchart to review the steps of forming an ionic bond. Use the notes and the flowchart to name the following ionic compounds. 16. NaI 17. CrF 18. BaO 19. CaF NaCl 21. Ag 2 S

A. Stock System If the compound contains a polyatomic ion. Steps for naming compounds with a polyatomic ion.  1.) Find the polyatomic ion on your list. Remember that most polyatomic ions are (-) so chances are it’s the second thing written.  2.) Name the first element or polyatomic ion, and then name the second element or polyatomic ion.  3.) If the second ion is not the polyatomic atom then be sure to add –ide.  Examples: Na 3 PO 4 – Sodium Phosphate NH 4 Cl- Ammonium Chloride

Example One Write the proper name for Be(OH) 2  1.) Find the polyatomic ion on your list. Remember that most polyatomic ions are (-) so chances are it’s the second thing written  2.) Name the first element or polyatomic ion, and then name the second element or polyatomic ion. If the second ion is not the polyatomic atom then be sure to add –ide.

Example Two Write the proper name for Ca 3 (PO 4 ) 2  1.) Find the polyatomic ion on your list. Remember that most polyatomic ions are (-) so chances are it’s the second thing written  2.) Name the first element or polyatomic ion, and then name the second element or polyatomic ion. If the second ion is not the polyatomic atom then be sure to add –ide.

Forming Ionic Compounds  Ionic compounds always have an overall charge of zero  Criss-cross method  Write the formula unit for when magnesium and nitrogen combine:  Potassium + Oxygen=  Magnesium + Sulfur=  Beryllium + Carbon=  Aluminum + Phosphate=  Potassium + Hydroxide=

A. Stock System If the compound contains a transition metal (D-Block)  You must include a Roman numeral that denotes the charge on the transition metal.  For instance, Fe2+ is iron (II). Fe3+ is iron (III)  Example: FeBr 2 Iron (II) Bromide

Example One Write the proper name for FeO.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first :  Step 3: Determine the charge of the cation- remember that the charges of the cation and the anion must balance out (equal zero). Write the charge of the cation in roman numerals in parenthesis after the cation’s symbol.  Step 4: Write the name of the element that is the anion second. If the second ion is not a polyatomic ion then be sure to change the ending to “ide”  Step 5: Put step 3 and step 4 together and you have the correct name for the compound.

Example Two Write the proper name for CuSO 3.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first :  Step 3: Determine the charge of the cation- remember that the charges of the cation and the anion must balance out (equal zero). Write the charge of the cation in roman numerals in parenthesis after the cation’s symbol.  Step 4: Write the name of the element that is the anion second. If the second ion is not a polyatomic ion then be sure to change the ending to “ide”  Step 5: Put step 3 and step 4 together and you have the correct name for the compound.

Example Three Write the proper name for Pb(SO 3 ) 2.  Step 1: Determine the charge of the cation and anion in the compound.  Which element has a positive charge and is a cation?  Which element has a negative charge and is a anion?  Step 2: Write the name of the element that is the cation first :  Step 3: Determine the charge of the cation- remember that the charges of the cation and the anion must balance out (equal zero). Write the charge of the cation in roman numerals in parenthesis after the cation’s symbol.  Step 4: Write the name of the element that is the anion second. If the second ion is not a polyatomic ion then be sure to change the ending to “ide”  Step 5: Put step 3 and step 4 together and you have the correct name for the compound.

B. Molecular System (Covalent Bonds)  1=mono  2=di  3=tri  4=tetra  5=penta * Mono is never used on the first atom written, only the second atom.  2.) Add the prefix to the name of the first element (unless there is only one atom).  3.) Add the prefix to the name of the second element. Drop the ending of the second atom written and add – IDE. In order to name covalent or metallic compounds, you have to know the prefixes used to describe the numbers scientists use in Chemistry. 1.) Use prefixes to state how many atoms are present.  6= hexa  7=hepts  8=octa  9=nona  10=deca

Example One Write the proper name for CO 2  Step 1: Determine how many atoms are in the first element in the compound  Step 2: Determine what prefix this number represents  Step 3: Add the prefix onto the front part of the elements name:  Step 4: Determine how many atoms are in the second element in the compound:  Step 5: Determine what prefix this number represents:  Step 6: Add the prefix onto the front part of the elements name and add “ide” on to the end:  Step 7: Add Step 3 and Step 6 together and you get:

Example Two Write the proper name for Li 2 Be  Step 1: Determine how many atoms are in the first element in the compound  Step 2: Determine what prefix this number represents  Step 3: Add the prefix onto the front part of the elements name:  Step 4: Determine how many atoms are in the second element in the compound:  Step 5: Determine what prefix this number represents:  Step 6: Add the prefix onto the front part of the elements name and add “ide” on to the end:  Step 7: Add Step 3 and Step 6 together and you get:

Example Three Write the proper name for P 2 S 3  Step 1: Determine how many atoms are in the first element in the compound  Step 2: Determine what prefix this number represents  Step 3: Add the prefix onto the front part of the elements name: NOTE: IF there is only ONE atom of the first element- you DO NOT add the prefix mono to it. This is the ONLY exception to the rule.  Step 4: Determine how many atoms are in the second element in the compound:  Step 5: Determine what prefix this number represents:  Step 6: Add the prefix onto the front part of the elements name and add “ide” on to the end:  Step 7: Add Step 3 and Step 6 together and you get:

Review Stock System (Ionic Bonds) and Molecular System (Covalent Bonds) 1.P 4 O 10 2.SeCl 2 3.NO 4.N 2 O 5.NO 2  Look over the flowchart to review the steps of forming an ionic bond. Use the notes and the flowchart to name the following ionic compounds.  How do you know which naming system to use? 6.SF 8 7.BCl 3 8.CoCO 3 9.FePO 4 10.Cu 2 S