Chemistry Chapter 7:
Chemical Formulas & Compounds
TEXT REFERENCE: Chapter 7
INCLUDED:
CONTENT PAGE(s)
CLASS NOTES (web material):
Chapter 7: Part 1 - Chemical Names and Formulas 2–4
Naming Compounds and Writing Formulas Flowcharts 5
Another flowchart for naming compounds 6
Assigning Oxidation Numbers: Key Rules 7
WORKSHEETS:
Chapter 7 vocabulary 8
Binary Ionic Compounds worksheet 9
Ternary Ionic Compounds - Unit 5 Worksheet 2 10
Mixed Naming Ionic Compounds Practice Worksheet 11
Extra Practice – Writing Ionic Formulas 12
Molecular Compounds - Unit 5 Worksheet 3 13
Chemistry: Naming Covalent Compounds Worksheet 14
Naming Covalent Compounds 2 15
Naming Ionic and Covalent Compounds 1 16
Naming Ionic and Covalent Compounds 2 17
Test Review – Mixed Naming Practice 18
Determining Oxidation Numbers 19
Oxidation States Worksheet 20
Molar Mass Calculations Worksheet 21
Moles to Grams, Grams to Moles conversion Worksheet 22
Grams/Moles/Molecules Conversions Worksheet 23
Moles, Molecules, and Grams Worksheet 2 24 – 25
Chapter 7 Class Notes: Part 2 – Overview of Calculations 26 – 27
Percent Composition Practice 28
Percent Composition Worksheet II 29
Empirical Formula Practice 1 30
Empirical Formula Practice 2 31
Molecular Formula Worksheet 32
Empirical and Molecular Formula Worksheet 1 33
Homework 5-5 Molecular Formula 34
Molecular Formula Worksheet 2 35
Mixed Calculations Review Worksheet 36
Concept Review: Chemical Formulas and Chemical Compounds 37
Concept Review 2: Ionic vs Molecular Compounds 38
Chapter 7 Test Review Problems 39 – 40
LABS:
Percent Composition of Hydrates 41 – 44
1
,Chapter 7: Part 1 - Chemical Names and Formulas
2
,Ionic Charges & Types of ions
● Monatomic Cations (single type of element)
○ these cations are formed when metals lose electrons
○ these cations will have the same name as the element itselt
○ the metals in Groups 1, 2, and 13 will always have the same charge
- Group 1 metals (alkali metals) all lose one electron to get a +1 charge
- Group 2 metals (alkaline earth metals) all lose two electrons to get a +2 charge
- Group 13 metals lose three electrons to get a +3 charge
○ the transition metals (Groups 3-12) and metals in Groups 14 and 15 have several
possibilities for charges:
- A Roman numeral is used to indicate the charge of the cation
- EXAMPLE: Fe2+ is called iron (II) and pronounced “Iron Two”
- 3 exeptions: Ag (in Group 11) is always 1+; Zn and Cd (in Group 12) are always 2+
● Monatomic Anions (single type of element)
○ these anions are formed when nonmetals gain electrons
○ the name of the anion has the same root (beginning)as that of the nonmetal but ends with the
suffix “ide”
○ the nonmetals in Groups 15, 16, and 17 will always have the same charge
- Group 15 nonmetals all gain three electrons to get a -3 charge
- Group 16 nonmetals all gain two electrons to get a -2 charge
- Group 17 nonmetals (halogens) all gain one electron to get a -1 charge
○ Group 18(noble gases) are nonmetals but do not gain or lose electrons and are neutral (“0”)
● Polyatomic Anions (more than one type of element)
○ Polyatomic ions are groups of atoms, covalently bonded, which carry a charge
○ Polyatomic ions act as a unit and form an ionic bond with an ion of an opposite charge
○ In compound names, the name of the polyatomic ion is not changed.
○ Most polyatomic ions end in “ate” or “ite”. Exeptions include CN- and OH- (both end in “ide”) and
positively-charged polyatomic ions, e.g. NH 4+ and H3O+ which end in “ium”
BINARY Compounds.
○ binary compounds contain only two different types of elements
○ If both elements are nonmetals, the form a binary molecular compound;
○ If one element is a metal (cation) and the other a nonmetal (anion), they form a binary ionic
compound.
○ Ionic and molecular compounds have different naming schemes:
3
, Naming Compounds
BINARY IONIC Compounds.
○ Name the CATION first and the ANION second
○ The cation name is the same as the element itself
○ If the cation can have more than one charge (most transition metals, Groups 14 and 15 metals),
designate the charge on the cation with a Roman numeral after the name. EX: Copper (II) for
Cu2+
○ The anion name is the root of the nonmetal atom’s name with the suffix “ide”: EX: oxide for O 2-
Binary compounds always end with “ide”
TERNARY IONIC Compounds (contain at least one polyatomic ion)
Similarity to Binary Ionic Compounds:
○ Name the CATION first and the ANION second
○ The cation name is the same as the cation itself –the name of the element OR the positively-
charged polyatomic ion, e.g. NH4+ is ammonium;
○ If the cation can have more than one charge (most transition metals, Groups 14 and 15 metals),
designate the charge on the cation with a Roman numeral after the name. EX: Copper (II) for
Cu2+
Difference from Binary Ionic Compounds:
○ If the anion is a polyatomic ion, DO NOT CHANGE THE NAME. EX: SO 42- is sulfate NOT sulfide.
The suffix “ide” is used for MONOATOMIC anions and a few specific polyatomic ions whose name
ends in “ide”, e.g. cyanide and hydroxide.
BINARY MOLECULAR Compounds: 2 NONmetal elements
○ In naming molecular compounds, the first nonmetal retains its elemental name and the second
nonmetal has the ending changed to “ide.
○ The LEAST electronegative atom is given first AND has the same name as the element itself
○ The MORE electronegative atom is given second; the name is the root of element with the suffix
“ide”, EX: chloride.
○ PREFIXES are used to indicate how many of each element are listed in the formula.
○ Know the prefixes mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca
○ Exception: The prefix “mono” is NOT used for the first word of the compound’s name.
○ Prefixes are sometimes shortened to make the name easier to say (especially when a prefix
comes up next to oxygen or oxide). EX: use “tetroxide” NOT “tetraoxide”.
Writing Formulas
IONIC Compounds (binary or ternary)
○ The cation is written first and the anion second in the formula
○ The number of each element is calculated from the charges on the cation and anion.
○ The sum of the charges must equal zero in an ionic compound
○ The absolute value of the charge on the anion is equal to the number of cations in the formula
and the absolute value of the charge on the cation is equal to the number of anions
- This is known as the “criss-cross” method of determining the formula
EXCEPTION: The subscripts should be simplified to the smallest whole number integers of each
ion:
EX: lead (IV) oxide is PbO2 NOT Pb2O4
○ If there is more than one polyatomic ion in the formula, encase the ion formula in parentheses and
put the subscript outside the parentheses. EX: Ca(NO3)2
Molecular Compounds
○ The prefixes tell you how many of each element there is in the formula – these become the
subscripts in the formula.
○ Write the symbols for the elements in the same order as in the name:
EX: dintirogen tetraoxide has 2 N and 4 O, written as N2O4
4
Chemical Formulas & Compounds
TEXT REFERENCE: Chapter 7
INCLUDED:
CONTENT PAGE(s)
CLASS NOTES (web material):
Chapter 7: Part 1 - Chemical Names and Formulas 2–4
Naming Compounds and Writing Formulas Flowcharts 5
Another flowchart for naming compounds 6
Assigning Oxidation Numbers: Key Rules 7
WORKSHEETS:
Chapter 7 vocabulary 8
Binary Ionic Compounds worksheet 9
Ternary Ionic Compounds - Unit 5 Worksheet 2 10
Mixed Naming Ionic Compounds Practice Worksheet 11
Extra Practice – Writing Ionic Formulas 12
Molecular Compounds - Unit 5 Worksheet 3 13
Chemistry: Naming Covalent Compounds Worksheet 14
Naming Covalent Compounds 2 15
Naming Ionic and Covalent Compounds 1 16
Naming Ionic and Covalent Compounds 2 17
Test Review – Mixed Naming Practice 18
Determining Oxidation Numbers 19
Oxidation States Worksheet 20
Molar Mass Calculations Worksheet 21
Moles to Grams, Grams to Moles conversion Worksheet 22
Grams/Moles/Molecules Conversions Worksheet 23
Moles, Molecules, and Grams Worksheet 2 24 – 25
Chapter 7 Class Notes: Part 2 – Overview of Calculations 26 – 27
Percent Composition Practice 28
Percent Composition Worksheet II 29
Empirical Formula Practice 1 30
Empirical Formula Practice 2 31
Molecular Formula Worksheet 32
Empirical and Molecular Formula Worksheet 1 33
Homework 5-5 Molecular Formula 34
Molecular Formula Worksheet 2 35
Mixed Calculations Review Worksheet 36
Concept Review: Chemical Formulas and Chemical Compounds 37
Concept Review 2: Ionic vs Molecular Compounds 38
Chapter 7 Test Review Problems 39 – 40
LABS:
Percent Composition of Hydrates 41 – 44
1
,Chapter 7: Part 1 - Chemical Names and Formulas
2
,Ionic Charges & Types of ions
● Monatomic Cations (single type of element)
○ these cations are formed when metals lose electrons
○ these cations will have the same name as the element itselt
○ the metals in Groups 1, 2, and 13 will always have the same charge
- Group 1 metals (alkali metals) all lose one electron to get a +1 charge
- Group 2 metals (alkaline earth metals) all lose two electrons to get a +2 charge
- Group 13 metals lose three electrons to get a +3 charge
○ the transition metals (Groups 3-12) and metals in Groups 14 and 15 have several
possibilities for charges:
- A Roman numeral is used to indicate the charge of the cation
- EXAMPLE: Fe2+ is called iron (II) and pronounced “Iron Two”
- 3 exeptions: Ag (in Group 11) is always 1+; Zn and Cd (in Group 12) are always 2+
● Monatomic Anions (single type of element)
○ these anions are formed when nonmetals gain electrons
○ the name of the anion has the same root (beginning)as that of the nonmetal but ends with the
suffix “ide”
○ the nonmetals in Groups 15, 16, and 17 will always have the same charge
- Group 15 nonmetals all gain three electrons to get a -3 charge
- Group 16 nonmetals all gain two electrons to get a -2 charge
- Group 17 nonmetals (halogens) all gain one electron to get a -1 charge
○ Group 18(noble gases) are nonmetals but do not gain or lose electrons and are neutral (“0”)
● Polyatomic Anions (more than one type of element)
○ Polyatomic ions are groups of atoms, covalently bonded, which carry a charge
○ Polyatomic ions act as a unit and form an ionic bond with an ion of an opposite charge
○ In compound names, the name of the polyatomic ion is not changed.
○ Most polyatomic ions end in “ate” or “ite”. Exeptions include CN- and OH- (both end in “ide”) and
positively-charged polyatomic ions, e.g. NH 4+ and H3O+ which end in “ium”
BINARY Compounds.
○ binary compounds contain only two different types of elements
○ If both elements are nonmetals, the form a binary molecular compound;
○ If one element is a metal (cation) and the other a nonmetal (anion), they form a binary ionic
compound.
○ Ionic and molecular compounds have different naming schemes:
3
, Naming Compounds
BINARY IONIC Compounds.
○ Name the CATION first and the ANION second
○ The cation name is the same as the element itself
○ If the cation can have more than one charge (most transition metals, Groups 14 and 15 metals),
designate the charge on the cation with a Roman numeral after the name. EX: Copper (II) for
Cu2+
○ The anion name is the root of the nonmetal atom’s name with the suffix “ide”: EX: oxide for O 2-
Binary compounds always end with “ide”
TERNARY IONIC Compounds (contain at least one polyatomic ion)
Similarity to Binary Ionic Compounds:
○ Name the CATION first and the ANION second
○ The cation name is the same as the cation itself –the name of the element OR the positively-
charged polyatomic ion, e.g. NH4+ is ammonium;
○ If the cation can have more than one charge (most transition metals, Groups 14 and 15 metals),
designate the charge on the cation with a Roman numeral after the name. EX: Copper (II) for
Cu2+
Difference from Binary Ionic Compounds:
○ If the anion is a polyatomic ion, DO NOT CHANGE THE NAME. EX: SO 42- is sulfate NOT sulfide.
The suffix “ide” is used for MONOATOMIC anions and a few specific polyatomic ions whose name
ends in “ide”, e.g. cyanide and hydroxide.
BINARY MOLECULAR Compounds: 2 NONmetal elements
○ In naming molecular compounds, the first nonmetal retains its elemental name and the second
nonmetal has the ending changed to “ide.
○ The LEAST electronegative atom is given first AND has the same name as the element itself
○ The MORE electronegative atom is given second; the name is the root of element with the suffix
“ide”, EX: chloride.
○ PREFIXES are used to indicate how many of each element are listed in the formula.
○ Know the prefixes mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca
○ Exception: The prefix “mono” is NOT used for the first word of the compound’s name.
○ Prefixes are sometimes shortened to make the name easier to say (especially when a prefix
comes up next to oxygen or oxide). EX: use “tetroxide” NOT “tetraoxide”.
Writing Formulas
IONIC Compounds (binary or ternary)
○ The cation is written first and the anion second in the formula
○ The number of each element is calculated from the charges on the cation and anion.
○ The sum of the charges must equal zero in an ionic compound
○ The absolute value of the charge on the anion is equal to the number of cations in the formula
and the absolute value of the charge on the cation is equal to the number of anions
- This is known as the “criss-cross” method of determining the formula
EXCEPTION: The subscripts should be simplified to the smallest whole number integers of each
ion:
EX: lead (IV) oxide is PbO2 NOT Pb2O4
○ If there is more than one polyatomic ion in the formula, encase the ion formula in parentheses and
put the subscript outside the parentheses. EX: Ca(NO3)2
Molecular Compounds
○ The prefixes tell you how many of each element there is in the formula – these become the
subscripts in the formula.
○ Write the symbols for the elements in the same order as in the name:
EX: dintirogen tetraoxide has 2 N and 4 O, written as N2O4
4
