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Chapter 9. Chemical Names and Formulas. Section 1. Naming Ions. Section 1 Learning Targets. 9.1.1 – I can identify the charges of monatomic ions by using the periodic table, and name the ions.
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Chapter 9 Chemical Names and Formulas
Section 1 Naming Ions
Section 1 Learning Targets 9.1.1 – I can identify the charges of monatomic ions by using the periodic table, and name the ions. 9.1.2 – I can define a polyatomic ion and write the names and formulas of the most common polyatomic ions. 9.1.3 – I can identify the two common endings for the names of most polyatomic ions.
Monatomic Ions • Monatomic ion – consist of a single atom with a positive or negative charge resulting from the gain or loss of one or more valence electrons.
Cations • When the metals in Groups 1A, 2A and 3A lose electrons they form cations with positive charges equal to the group number. • The names of these ions are the same as the element name with ion after it.
Anions • Nonmetals of Groups 5A, 6A, and 7A gain electrons to form anions with negative charges. • The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number.
Group 7A so 7-8=-1; 6A so 6-8=-2; 5A so 5-8=-3 • The names of these ions change. The endings are dropped and replaced by –ide ion (sulfur = sulfide ion). • Groups 4A and 8A elements do not usually form ions.
Examples: • Name the ions formed by these elements and classify them as anions or cations: • Selenium ____________________ • Barium ____________________ • Phosphorus ____________________
Examples: • Name the following ions: • I- ____________________ • N3- ____________________ • O2- ____________________
Ions of Transition Metals • The charges of the cations of many transition metal ions must be determined from the number of electrons lost.
Two methods – classical (-ous and –ic endings) or the stock system (roman numerals). • Preferred is the stock system because the roman numeral tells the charge. So why do we use Roman numerals or the classical method anyway?
Examples: • Name the following ions: • Fe3+ ____________________ • Cu+ ____________________ • Mn4+ ____________________ • Sn2+ ____________________ • Pb4+ ____________________
Polyatomic Ions • Polyatomic ion – composed of more than one atom. • The names of most polyatomic anions end in –ate or –ite. • There are very few positive polyatomic ions.
Examples: • Write the symbol or formula (including charge) for each of the following ions: • Ammonium ion ____________________ • Chromate ion ____________________ • Tin (II) ion ____________________ • Nitrate ion ____________________
Examples: • Name the following ions: • OH- ____________________ • Pb4+ ____________________ • SO42- ____________________ • O2- ____________________
Section 2 Naming and Writing Formulas for Ionic Compounds
Section 2 Learning Targets 9.2.1 – I can apply the rules for naming and writing formulas for binary ionic compounds. 9.2.2 – I can apply the rules for naming and writing formulas for compounds with polyatomic ions.
Binary Ionic Compounds • In the past anyone who created a compound named it. • Currently there is a system. • Antione Lavoisier decided it was too difficult to memorize unrelated names and formulas.
Naming Binary Ionic Compounds • Binary compound – compound of two elements and can be either ionic or molecular. • To name binary ionic compounds, place the name of the cation first followed by the anion name.
Examples: • Write the names of the following binary ionic compounds: • NaCl ____________________ • MgBr2 ____________________ • SrO ____________________ • Li2O ____________________ • Be3N2 ____________________
For transition metals you need to figure the charge of the metal and put that in parentheses as a Roman numeral.
Examples: • Write the names of the following binary ionic compounds: • SnO2 ____________________ • Fe2O3 ____________________ • MnO ____________________ • MnO2 ____________________ • Co3N2 ____________________
Writing Formulas for Binary Ionic Compounds • Write the symbol of the cation and then the anion. • Add what ever subscripts are needed to balance the charges.
Examples: • Write the formulas for the compounds formed from these pairs of ions: • Ba2+, S2- ____________________ • Ca2+, N3- ____________________ • Li+, O2- ____________________ • Cu2+, I- ____________________
Examples: • Write the formulas for these compounds: • Sodium iodide ____________________ • Potassium sulfide ____________________ • Calcium iodide ____________________
For transition metals the Roman numeral tells the charge on the metal cation. • Then the same as before, balance the charges.
Examples: • Write the formulas for the following compounds: • Tin (IV) nitride ____________________ • Copper (I) oxide ____________________ • Copper (II) oxide ____________________ • Lead (II) sulfide ____________________ • Iron (III) oxide ____________________
Compounds with Polyatomic Ions • Write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges. • HINT: if you need more than one polyatomic ion – use parenthesis.
Examples: • Write the formula for the following compounds: • Ammonium nitride ____________________ • Ammonium cyanide ___________________ • Calcium carbonate ____________________ • Tin (IV) sulfite ____________________ • Magnesium phosphate __________________
Naming Compounds with Polyatomic Ions • To name a compound containing a polyatomic ion, state the cation first and then the anion, just as you did for binary ionic compounds.
Examples: • Name the following compounds: • Sn2(CO3)4 ____________________ • Mg(CN)2 ____________________ • Fe(NO3)3 ____________________ • (NH4)3PO4 ____________________ • CuSO4 ____________________
Section 3 Naming and Writing Formulas for Molecular Compounds
Section 3 Learning Targets 9.3.1 – I can interpret the prefixes in the names of molecular compounds in terms of their chemical formulas. 9.3.2 – I can apply the rules for naming and writing formulas for binary molecular compounds.
Naming Binary Molecular Compounds • Remember binary means 2. • Molecular compounds have covalent bonds – not ionic like previous sections.
A prefix in the name of a binary molecular compound tells you how many atoms of each element are present in each molecule of the compound. • Ending is still –ide so make sure you’re telling the difference between molecular and ionic.
Examples: • Write the name for the following binary molecular compounds: • NCl3 ____________________ • SO3 ____________________ • NI3 ____________________ • N2O3 ____________________ • N2H4 ____________________
Writing Formulas for Binary Molecular Compounds • Use the prefixes in the name to tell you the subscripts of each element in the formula. • Then write the correct symbols for the two elements with the appropriate subscripts.
Examples: • Write the formulas for the following binary molecular compounds: • Phosphorus pentachloride __________________ • Iodine heptafluoride ____________________ • Chlorine trifluoride ____________________ • Iodine dioxide ____________________ • Diphosphorus trioxide ____________________
Section 4 Naming and Writing Formulas for Acids and Bases
Section 4 Learning Targets 9.4.1 – I can apply three rules for naming acids. 9.4.2 – I can apply the rules in reverse to write the formulas for acids. 9.4.3 – I can apply the rules for naming bases.
Naming Acids • Acid – a compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water.
Rules for Naming Acids • When the name of the anion (X) ends in –ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix –icand is followed by the word acid. • HCl(aq) (X = chloride) is named hydrochloric acid. • H2S(aq) (X = sulfide) is named hydrosulfuric acid.
When the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid. • H2SO3(aq) (X = sulfite) is named sulfurous acid.
When the anion name ends in –ate, the acid name is the stem of the anion with the suffix –ic followed by the word acid. • HNO3(aq) (X = nitrate) is named nitric acid.
Examples: • Write the names for the following acids: • HNO2 ____________________ • HCN ____________________ • HMnO4 ____________________ • H2S ____________________ • HClO4 ____________________