Chemistry: A Self-Teaching Guide - Post R., Snyder C., Houk C.C. 2020

Nomenclature

Just as you have a given name by which you are recognized, every chemical compound has a name that makes it readily identifiable to every chemist.

In Chapter 4 you were introduced to molecular formulas that indicate the ratio of the combining elements. Our task in this chapter is to teach you how to name a compound when given its molecular formula, and vice versa. To be proficient in naming compounds and writing formulas (and later in writing and balancing chemical equations, Chapter 6), you should begin to memorize the oxidation numbers (valence charge) of the more common elements and groups of atoms that form what we call polyatomic ions. A table of common oxidation numbers is found on page 107.

Just as we are given nicknames by friends and become known by names that are not really our own names, the designation of chemical compounds is sometimes complicated by the use of common names that have been carried through the years. The establishment of an international nomenclature scheme, which we will study in this chapter, is an attempt to clear up this difficulty.

OBJECTIVE

After completing this chapter, you will be able to correctly name binary and ternary compounds, including binary and oxyacids and their salts, when given the correct chemical formula, and vice versa.

Chemical formulas are the chemist's international shorthand for describing a substance being studied. A chemical formula specifies what elements and how many atoms of each element are present in any substance.

Before we start naming compounds and writing formulas, we must cover a few ground rules. We present them here collectively and then separately as we work through the chapter. The scheme that we present is used for inorganic compounds composed of metals and nonmetals, as opposed to organic compounds that consist mainly of C, H, and O and a few other elements. The nomenclature of organic compounds is entirely different. You will be introduced to organic compounds in Chapter 14.

The first compounds we will discuss are binary compounds that contain only two elements. One element is usually a metal and the second element is a nonmetal. Remember that metals are found in Groups IA, IIA, IIIA, all the B groups, and toward the bottom of Groups IVA, VA, and VIA in the periodic table. Metals form positive charges by giving up electrons. The number of metals is much larger than the number of nonmetals. Nonmetals are located in the upper right-hand portion of the periodic table and form negative charges by gaining electrons.

The rules for naming binary compounds are:

· The symbol of the metallic or positively charged element is written first in the formula and named first.

· The symbol of the nonmetallic or negatively charged element is written and named second.

· The name of the metal remains unchanged, but the name of the nonmetal carries the suffix ide.

· CaO — calcium oxide

· LiF — lithium fluoride

· Common groups of elements (polyatomic ions) are treated as a single element.

· NH₄⁺ — ammonium ion

· OH^— — hydroxide ion

· CN^— — cyanide ion

These are specified in this way.

· If you check the table of charges on page 107, you will note that each formula we have written above is electrically neutral. That is, the sum of all the positive and negative charges is zero. We chose elements and polyatomic ions that carried numerically the same charge. What if we had chosen Li⁺ and O²⁻ to form a compound? The formula would be Li₂O because it must be electrically neutral (2Li⁺ = 2+, 1O²⁻ = 2−, 2+ and 2− add up to zero). Li₂O means two atoms of Li combined with one atom of O. We use small whole numbers as subscripts to make the formula electrically neutral.

· Ba²⁺ and I⁻ form BaI₂, barium iodide

· Al³⁺ and OH⁻ form Al(OH)₃, aluminum hydroxide

· Rb and S²⁻ form Rb₂S, rubidium sulfide

In the next section we will learn to name and write the formulas for some binary compounds.

TABLE OF COMMON OXIDATION NUMBERS

BINARY COMPOUNDS

Common table salt is called sodium chloride by chemists. Knowing that NaCl is sodium chloride will help you to remember the names of a whole class of chemical compounds. Two-element compounds are classified as binary compounds. Because NaCl contains two elements, it is classified as a __________ compound.

Answer: binary

The names of all binary compounds end in the letters ide. Note that the written name of NaCl is sodium chloride. The compound KCl is called potassium __________.

Answer: chloride

The compound CaS is called __________.

Answer: calcium sulfide

Na₂O is called __________.

Answer: sodium oxide

Several common ions, called polyatomic ions, are treated as single elements. The ammonium ion (NH₄⁺) is treated as a single element and is named first in a compound. The hydroxide ion (OH^—) and the cyanide ion (CN^—) are also treated as single elements in naming. These two are named last.

Give the name for each of the following.

1. NH₄Cl __________

2. KCN __________

3. NH₄I __________

4. HCl __________

Answer: (a) ammonium chloride; (b) potassium cyanide; (c) ammonium iodide; (d) hydrogen chloride

Give the formula for each of the following.

1. lithium hydroxide __________

2. ammonium hydroxide _______

3. barium hydroxide __________

4. hydrogen bromide __________

Answer: (a) LiOH; (b) NH₄OH; (c) Ba(OH)₂; (d) HBr

Now give the formula for each of the following.

1. potassium sulfide __________

2. magnesium sulfide __________

3. aluminum sulfide __________

Answer: (a) K₂S; (b) MgS; (c) Al₂S₃ (2Al³⁺ = 6+, 3S^2— = 6−, 6+ and 6− = 0)

You may have noticed that some common metallic elements, such as iron, copper, gold, chromium, mercury, tin, and lead, can have more than one oxidation number (other than zero). This means that iron can combine with chlorine to form two different compounds: FeCl₂ and FeCl₃. We can't call them both iron chloride so we must do something else.

There are two accepted methods of naming compounds containing these metals. One method is to write the oxidation number of the metal in Roman numerals to the right of the metal name followed by the name of the nonmetal with its suffix ide. For example, FeCl₂ is named “iron(II) chloride” because iron in this compound has an oxidation number of 2+ and Cl is 1−. FeCl₃ is named “iron(III) chloride” because iron in this compound has an oxidation number of 3+.

In the compound FeI₂, iron has an oxidation number of 2+. FeI₂ is named iron(_______) iodide.

Answer: II

In the compound Fe(OH)₃, iron has an oxidation number of 3+. Fe(OH)₃ is named __________________

Answer: iron(III) hydroxide

Iron, copper, gold, chromium, tin, lead, and mercury can form ions with two oxidation numbers.

1. In the compound CuO, the oxidation number of O is 2−. Thus, the oxidation number of copper is __________.

2. The name of CuO is __________.

Answer: (a) 2+ (charges must add up to zero); (b) copper(II) oxide

Given the compound Cu₂O:

1. The oxidation number of copper in the compound is __________.

2. The name of the compound is __________.

Answer: (a) 1+; (b) copper(I) oxide

As we mentioned, iron, copper, gold, chromium, mercury, lead, and tin are metals that can form ions with two (or more) oxidation numbers.

What is the oxidation number of the metal and the name of the compound for the following?

1. AuF₃ if F = 1−__________, __________

2. SnCl₄ if Cl = 1−__________, __________

3. PbO₂ if O = 2−__________, __________

4. Cr₂O₃ if O = 2−__________, __________

Answer: (a) 3+, gold(III) fluoride; (b) 4+, tin(IV) chloride; (c) 4+, lead(IV) oxide; (d) 3+, chromium(III) oxide

What are the formulas for the following compounds?

1. chromium(II) bromide__________

2. lead(II) hydroxide__________

3. gold(I) cyanide__________

4. mercury(II) oxide__________

Answer: (a) CrBr₂; (b) Pb(OH)₂; (c) AuCN; (d) HgO

An older method of naming compounds made from these metals (iron, copper, gold, chromium, tin, mercury, and lead) is to add ic or ous to their Latin names of these metals.

The suffix ic is added to the name of the element when the higher oxidation state is used. The suffix ous is added to the element name when the lower oxidation state is displayed in a compound. For example:

Gold(I) is the same as aurous. Gold(III) is the same as auric. Therefore, AuCl could be named gold(I) chloride or aurous chloride.

Here are more applications of the naming method to our group of metals.

· Lead(II) is the same as plumbous. Lead(IV) is the same as plumbic.

· Mercury(I) is the same as mercurous. Mercury(II) is the same as mercuric.

· Tin(II) is the same as stannous. Tin(IV) is the same as stannic.

· Copper(I) is the same as cuprous. Copper(II) is the same as cupric.

· Iron(II) is the same as ferrous. Iron(III) is the same as ferric.

· Chromium(II) is the same as chromous. Chromium(III) is the same as chromic.

· Chromium(VI) is an exception, since chromium can have three different oxidation states.

· Chromium(VI) is also called perchromic, a name you will learn more about later.

1. Two names for Fe₂O₃ are _____________________________ and _____________________________.

2. Two names for CuOH are _____________________________ and _____________________________.

3. Two names for Cr₂S₃ are _____________________________ and _____________________________.

4. Two names for PbCl₂ are _____________________________ and _____________________________.

Answer: (a) iron(III) oxide, ferric oxide; (b) copper(I) hydroxide, cuprous hydroxide; (c) chromium(III) sulfide, chromic sulfide; (d) lead(II) chloride, plumbous chloride

Write the formulas for these compounds.

1. stannous fluoride _____________

2. mercuric iodide _____________

3. plumbous oxide _____________

4. stannic sulfide _____________

Answer: (a) SnF₂; (b) HgI₂; (c) PbO; (d) SnS₂

The most common metals capable of two (or more) oxidation states have been listed in frame 12. In binary compounds, the nonmetals have only one oxidation number. The halogens are all 1−; oxygen and sulfur are each 2−. The Group IA metals are all 1+, and the Group IIA metals are 2+.

Before you continue you should memorize the oxidation states of the metals, nonmetals, and polyatomic ions as listed on the Table of Common Oxidation Numbers on page 107.

Certain pairs of nonmetallic elements form more than one binary compound. Good examples are carbon and oxygen. They combine to form CO and CO₂. Because carbon is more metallic than oxygen, it is written first. Based upon what you have just learned about naming compounds, their names using Roman numerals would be, respectively, ____________________ and _____________________.

Answer: carbon(II) oxide; carbon(IV) oxide

Through previous experience you probably know CO is also commonly called carbon monoxide and CO₂ is carbon dioxide.

The prefixes mono (1), di (2), tri (3), tetra (4), penta (5), hexa (6), hepta (7), and octa (8) indicate the number of atoms of each element present in the compound. Many binary compounds of carbon, nitrogen, sulfur, and oxygen are named using prefixes instead of the Roman numeral scheme. The next few frames will illustrate how prefixes are used.

SO₂ is called sulfur dioxide. You might have called it monosulfur dioxide, but when naming binary compounds that have only one positive atom in the compound, the mono prefix is dropped. For example, CO₂ is carbon dioxide not monocarbon dioxide. CO is carbon monoxide, not monocarbon monoxide.

What is the name for SO₃? _________________

Answer: sulfur trioxide (one atom of sulfur, three atoms of oxygen)

Several binary compounds of oxygen and nitrogen are N₂O, NO, NO₂, N₂O₃, and N₂O₅. N₂O₃ is named di nitrogen trioxide. NO₂ is named nitrogen dioxide.

1. NO is named _______________

2. N₂O is named _______________

3. N₂O₅ is named _______________

Answer: (a) nitrogen monoxide; (b) dinitrogen monoxide;(c) dinitrogen pentoxide

Use the same system to name the following compounds.

1. CS₂ __________

2. BF₃ __________

3. CCl₄ __________

Answer: (a) carbon disulfide; (b) boron trifluoride; (c) carbon tetrachloride

Write the formula for the following compounds.

1. nitrogen triiodide __________

2. nitrogen dioxide __________

3. diphosphorus trioxide __________

4. diphosphorus pentoxide __________

5. dinitrogen tetroxide __________

Answer: (a) NI₃; (b) NO₂; (c) P₂O₃; (d) P₂O₅; (e) N₂O₄

Previously we have seen prefixes in parentheses used instead of oxidation numbers for binary compounds of metals when the metal has more than one possible oxidation number. For example, MnO₂ may be called manganese(IV) oxide or manganese dioxide. SeO₃ may be called selenium(VI) oxide or selenium trioxide. Likewise, N₂O₃ may be called dinitrogen trioxide or nitrogen(III) oxide.

What other name could be given for the following?

1. NO₂: nitrogen dioxide or __________

2. CCl₄: carbon tetrachloride or __________

3. P₂O₃: diphosphorus trioxide or __________

4. PbO₂: plumbic oxide, lead(IV) oxide, or __________

Answer: (a) nitrogen(IV) oxide; (b) carbon(IV) chloride; (c) phosphorus(III) oxide; (d) lead dioxide

What would be the formula for the following?

1. lead monoxide ____________________

2. carbon(IV) sulfide __________

Answer: (a) PbO; (b) CS₂

Placing the Roman numeral of the oxidation number of the first named element in the compound name, such as carbon(IV) oxide, is the method recommended by the International Union of Pure and Applied Chemistry (IUPAC) and is less confusing than other methods.

However, as long as other methods of naming exist, you should be able to translate back and forth between methods.

Remember that placing the Roman numeral of the oxidation number of the first element in a compound is valid only if the first-named element can have more than one oxidation number. If the first element can have only one oxidation number, we do not use the Roman numeral or a prefix on either name.

Name these compounds.

1. CaO __________

2. CO __________

3. K₃N __________

4. MnCl₃ __________

Answer: (a) calcium oxide (calcium has only one oxidation number); (b) carbon(II) oxide or carbon monoxide; (c) potassium nitride; (d) manganese(III) chloride or manganese trichloride

Write the formulas for these compounds.

1. manganese difluoride __________

2. chromium(VI) oxide __________

3. silicon dioxide __________

Answer: (a) MnF₂; (b) CrO₂; (c) SiO₂

BINARY ACIDS

One special class of compounds has the H⁺ ion serving in place of a metal ion in the compound. These compounds have special properties, which we will identify as acidic properties in Chapter 13. For now we will simply call them acids. The first names of these acids are combinations of prefixes and suffixes attached to the name of another nonmetal, and the second name is “acid.”

In these frames we will look at the scheme for naming binary acids. Remember, “binary” means only two elements are present. The compound HF can be named as a binary compound with the name _________.

Answer: hydrogen fluoride

The compound HF is an example of a binary acid. It can be named as an ordinary binary compound, or it can be named hydrofluoric acid. This method of naming substitutes hydro for hydrogen and adds the suffix ic to the stem or full name of the second element.

Name the binary acid HCl in two ways: ____________________ or ____________________.

Answer: hydrogen chloride; hydrochloric acid

You may already be familiar with HCl as hydrochloric acid. If you remember this name for HCl, you can remember the method for naming all binary acids.

HBr can be named ____________________ or ____________________.

Answer: hydrogen bromide; hydrobromic acid

Sulfur (S) and selenium (Se) both have only one negative oxidation number, 2−.

1. What would be the formula of the binary compounds formed between hydrogen and sulfur? __________ Between hydrogen and selenium? ___________

2. What are the names of those compounds? _________________________

Answer: (a) H₂S; H₂Se; (b) hydrogen sulfide or hydrosulfuric acid; hydrogen selenide or hydroselenic acid

Name H₂Te as an acid. __________

Answer: hydrotelluric acid

OXYACIDS

Some very common useful acids contain hydrogen, a nonmetal, and oxygen. Acids that contain these three elements are called oxyacids. The oxy in oxygen may help you to remember the term “oxyacid.”

The most common oxyacid is H₂SO₄, sulfuric acid. Another oxyacid is HNO₃, nitric acid. You may already be familiar with these acids.

Which of the following compounds are oxyacids: HCl, H₂SO₃, HI, H₂O, H₃PO₄? _______________

Answer: H₂SO₃, H₃PO₄

Oxyacids are probably the most difficult compounds to name because the same three elements may combine in different ratios. We know, for example, that H, S, and O combine to form H₂SO₄ and H₂SO₃; H, N, and O form HNO₃ and HNO₂. Phosphorus and the halogens form several oxyacids. The next few frames will present a scheme by which oxyacids may be named.

The most common forms of oxyacids are named by adding ic to the stem or name of the nonmetal in each acid. The ic acids usually contain either three or four oxygen atoms in their formulas, but there is no systematic way to know whether an ic acid contains three or four oxygen atoms. A handy way to remember whether an ic acid contains three or four oxygen atoms is to list several ic oxyacids alphabetically according to the first letter of the nonmetals symbol, as shown below. Note that as the alphabet reaches the letter O, the number of oxygen atoms in the ic acid increases from three to four.

HIO₃ follows the rule of thumb. What is the name of HIO₃? __________

Answer: iodic acid

H₂SeO₄ follows the rule of thumb. What is the name of H₂SeO₄? __________

Answer: selenic acid

Note that we have not included any reference to hydrogen in the names of oxyacids as we did with binary acids. Nor have we included prefixes (mono, di, or others). There is no need to do so since the name “acid” tells us there is hydrogen present, and the number of hydrogens present is a function of the oxidation number (charge) of the polyatomic ion with which it is combined.

Look at the table of common polyatomic ions on page 107 (if you need to) and see if you can find the polyatomic ion and its charge for the following ic acids.

1. H₃PO₄ __________

2. H₂SO₄ __________

3. HNO₃ __________

Answer: (a) PO₄³⁻; (b) SO₄²⁻; (c) NO₃⁻

Bromic acid follows the rule of thumb. What is the formula of bromic acid? ___________ What is the polyatomic ion and its charge? __________

Answer: HBrO₃; (the charge is 1−)

Chloric acid follows the rule of thumb. What is the polyatomic ion and its charge for chloric acid?________

Answer: (the charge is 1−)

Once you have learned the name and formula of the ic acid for any nonmetal, all other oxyacids with the same nonmetal are systematically named (e.g., H₂SO₄, H₂SO₃). If an oxyacid contains one less oxygen than the ic acid, it is named by using the same stem but changing the ic to ous. Since H₂SO₄ is sulfuric acid, H₂SO₃ is sulfurous acid.

HClO₃ is chloric acid. What is the formula for chlorous acid? __________

Answer: HCIO₂ (one less oxygen than the “ic” acid)

Write the formulas for the following acids.

1. Nitrous acid ______________

2. Phosphorous acid __________

Answer: (a) HNO₂; (b) H₃PO₃

Name the following compounds.

1. HBrO₂ __________

2. HIO₂ __________

3. H₂SeO₃ __________

Answer: (a) bromous acid; (b) iodous acid; (c) selenous acid

An acid with two less oxygens than the ic acid is named by dropping the ic and substituting ous, and placing the prefix hypo before the nonmetal. “Hypo” means under or beneath (such as in hypodermic, meaning under the skin). A “hypo-ous” acid has one less oxygen than an “ous” acid.

1. HClO₃ is __________ acid.

2. HClO₂ is __________ acid.

3. HClO is __________ acid.

Answer: (a) chloric; (b) chlorous; (c) hypochlorous

Write the formulas for these acids.

1. hypobromous acid __________

2. hypoiodous acid __________

3. hypophosphorous acid __________

Answer: (a) HBrO; (b) HIO; (c) H₃PO₂

In some cases it may be possible for an acid to have one more oxygen atom than the corresponding ic acid. Such an acid is named by placing the prefix per before the nonmetal and keeping the ic in the name.

1. HClO₃ is __________ acid.

2. HClO₄ is __________ acid.

Answer: (a) chloric; (b) perchloric

Use the naming rule for the following acids.

1. HBrO₃ is named __________.

2. HBrO₂ is named __________.

3. HBrO₄ is named __________.

Answer: (a) bromic acid; (c) bromous acid; (c) perbromic acid

Oxyacids really behave as though they have only two parts: the hydrogen ion(s) (H+) and the polyatomic ion. The polyatomic ion that we have discussed is called the acid polyatomic ion. For example, the acid polyatomic ion of HNO₃ is , in H₂SO₄ it is SO₄^2—, and in H₃PO₄ it is PO₄^3—. The acid polyatomic ion carries its own name, as you may have noticed in the table on page 107. The names of acid polyatomic ions for ic acids are derived by dropping the ic ending and replacing it with ate. For example, the polyatomic ion is called the nitrate polyatomic ion. The SO₄^2— polyatomic ion is called the sulfate polyatomic ion. The PO₄^3— polyatomic ion is called the ______________ polyatomic ion.

Answer: phosphate

What are the polyatomic ion names for the following acids?

1. HClO₃ __________

2. (b) HBrO₃ __________

Answer: (a) chlorate; (b) bromate

Similarly, ous acids have ite acid polyatomic ion names. For example, in HNO₂, nitrous acid, the is called the nitrite polyatomic ion. What is the acid polyatomic ion name for each of the following?

1. H₂SO₃ __________

2. HClO₂ __________

3. H₃PO₃ __________

Answer: (a) sulfite; (b) chlorite; (c) phosphite

“Hypo-ous” acids have “hypo-ite” polyatomic ions.

1. ClO⁻ is the __________ polyatomic ion.

2. IO⁻ is the __________ polyatomic ion.

3. PO₂^3— is the __________ polyatomic ion.

Answer: (a) hypochlorite; (b) hypoiodite; (c) hypophosphite

“Per-ic” acids have “per-ate” polyatomic ions.

1. is the __________ polyatomic ion.

2. is the __________ polyatomic ion.

Answer: (a) perchlorate; (b) perbromate

SALTS

A very large number of compounds are formed by combining acid polyatomic ions and metal ions. For example, Na⁺ and SO₄^2— form Na₂SO₄. Remember, the metal or most positive element is written first, the negative part is written second, and subscripts are used to make the positive charges and negative charges equal zero. These compounds formed from metal ions and acid polyatomic ions are called salts. In Chapter 13 you will see one way in which salts may be prepared in the laboratory. Salts are named by using the name of the metal followed by the name of the acid polyatomic ion. Thus, Na₂SO₄ is called sodium sulfate. It is derived from Na⁺ and SO₄^2—.

Salts derived from ic acids are called ate salts. The acid HClO₃ is named chloric acid. The salt KClO₃ is named __________.

Answer: potassium chlorate

H₂SO₄ is __________ acid. CaSO₄ is __________.

Answer: sulfuric; calcium sulfate

Try your hand with the following.

1. HNO₃ is _____________ acid.

2. The formula of the compound formed between Ba²⁺ and NO₃^— is ______________.

3. The compound of Ba²⁺ and NO₃^— is named _______________. (Remember, the NO₃^— acts as a single unit. It takes two polyatomic ions to balance Ba²⁺.)

Answer: (a) nitric; (b) Ba(NO₃)₂; (c) barium nitrate

HNO₃ is nitric acid. Al(NO₃)₃ is __________.

Answer: aluminum nitrate

HBrO₃ is __________ acid. Ca(BrO₃)₂ is __________.

Answer: bromic; calcium bromate

What are the formulas of the following compounds?

1. sodium iodate __________

2. magnesium sulfate __________

3. lithium phosphate __________

4. barium phosphate __________

Answer: (a) NalO₃; (b) MgSO₄; (c) Li₃PO₄; (d) Ba₃(PO₄)₂

Similarly, ous acids form ite salts, “hypo-ous” acids form “hypo-ite” salts, and “per-ic” acids form “per-ate” salts. HIO is _____________ acid. LiIO is ______________.

Answer: hypoiodous; lithium hypoiodite

HIO₄ is __________ acid. KIO₄ is __________.

Answer: periodic; potassium periodate

HBrO₂ is __________ acid. Mg(BrO₂)₂ is __________.

Answer: bromous; magnesium bromite

SUMMARY

You should now be able to write formulas and name compounds with a reasonable degree of proficiency. As with most rules there are exceptions, but you will not encounter them in this book. The decision tree on page 123 is a useful summary for naming compounds.

I. Binary compounds

1. Contain only two different elements.

2. Are named by:

1. Writing the name of the metal followed by the name of the nonmetal with an ide ending, or

2. Writing the name of the metal followed by the charge of the metal in Roman numerals in parentheses, then the nonmetal name with the ide ending, or

3. Using prefixes before the names of the elements with the ide ending on the name of the second element.

3. Formulas are written by using the symbol of the more metallic element followed by the symbol of the more nonmetallic element, with the necessary subscripts to make the charges equal zero.

II. Binary acids

1. Contain hydrogen and another nonmetal.

2. Are named by using a hydro prefix and an ic suffix with the name of the nonmetal.

3. Formulas are written with the hydrogen first and the other nonmetal second, with the appropriate subscripts to make the charges equal zero.

III. Oxyacids

1. Contain hydrogen, a nonmetal, and oxygen.

2. Are named according to the most commonly occurring acid, the ic acid. The suffix ic is added to the name of the nonmetal.

1. Acids with one less oxygen than the ic acid are ous acids.

2. Acids with two less oxygens than the ic acid are “hypo-ous” acids.

3. Acids with one more oxygen than the ic acid are “per-ic” acids.

3. Formulas are written with the hydrogen followed by the polyatomic acid ion, with necessary subscripts included to make the charges equal zero.

IV. Oxyacid salts

1. Contain a metal, a nonmetal, and oxygen.

2. Are derived from oxyacids.

3. Are named by writing the name of the metal followed by the name of the polyatomic acid ion.

1. ic acids form ate salts.

2. ous acids form ite salts.

3. Hypo-ous acids form hypo-ite salts.

4. Per-ic acids form per-ate salts.

4. Formulas are written with the metal symbol first followed by the polyatomic acid ion, with necessary subscripts to make the charges equal zero.

SELF-TEST

This self-test is designed to show how well you have mastered this chapter's objectives. Correct answers and review instructions follow the test.

1. Name the following compounds.

1. Kl __________

2. NaCN ________

3. (NH₄)₂SO₄ _______

4. CCl₄ ________

5. SeO₃ ________

6. Fe₂O₃ _______

7. N₂O₅ ___________

8. HCI _______

9. HNO₂ _____

10. KCIO _____

11. HIO₄ _____

12. Na₂SO₃ _____

13. Ba(OH)₂ _______

2. Write the formulas for the following compounds.

1. lithium bromide _____

2. carbon monoxide _____

3. copper(I) oxide ______

4. carbon(IV) disulfide ____

5. cupric hydroxide _____

6. ammonium carbonate _______

7. hypobromous acid _____

8. hydrosulfuric acid _____

9. sodium perchlorate _____

10. ammonium phosphate_____

11. ammonium nitrite _____________

12. iron(II) iodide or ferrous iodide _____

13. dinitrogen trioxide _____

3. What are the oxidation numbers for Cr, Sn, and Fe in the compounds CrCl₃, SnF₄, and Fe₂O₃?

4. What are the oxidation numbers for Cu, Au, and Pb in the compounds CuCl₂, AuCl, and PbO₂?

5. The two names for CuF are _____________________ and ____________________.

6. The two names for PbO₂ are ____________________ and ___________________.

7. The two names for HI are ____________________ and _____________________.

8. The two names for HBr are _________________ and ________________________.

9. Which of the following compounds are binary acids: HF, H₂SO₄, HBr, H₂O, HNO₃?

10. Which of the following compounds are oxyacids: HBr, H₂SO₄, HCl, H₂O, H₃PO₄?

11. What are the names for the following oxyacids: HClO₃, HBrO₃, HlO₃?

12. What are the names for the following oxyacids: HClO₄, HBrO₄, HlO₄?

13. Identify the compound that is chlorous acid: HClO₃, HClO₂, HClO.

14. Identify the compound that is hypobromous acid: HBrO₃, HBrO₂, HBrO.

15. The salt Hg₂(NO₃)₂ which has a formula of HgNO₃ but usually exists as the dihydrate and is thus written as Hg₂(NO₃)₂. The dihydrate formula does not change its name. Which of the following are correct names?: mercury(II) nitrate, mercury nitrate, mercurous nitrate, mercury(I) nitrate, mercuric nitrate.

ANSWERS

Compare your answers to the self-test with those given below. If you answer all questions correctly, you are ready to proceed to the next chapter. If you miss any, review the frames indicated in parentheses following the answers. If you miss several questions, you should probably reread the chapter carefully.

1.

1. potassium iodide (frames 1—24)

2. sodium cyanide (frames 1—24)

3. ammonium sulfate (frames 48—56)

4. carbon tetrachloride (frames 1—24)

5. selenium trioxide or selenium(VI) oxide (frames 1—24)

6. iron(III) oxide or ferric oxide (frames 1—24)

7. dinitrogen pentoxide or nitrogen(V) oxide (frames 1—24)

8. hydrogen chloride or hydrochloric acid (frames 25—29)

9. nitrous acid (frames 30—47)

10. potassium hypochlorite (frames 48—56)

11. periodic acid (frames 30—47)

12. sodium sulfite (frames 48—56)

13. barium hydroxide (frames 1—24)

2.

1. LiBr (frames 1—24)

2. CO (frames 1—24)

3. Cu₂O (frames 1—24)

4. CS₂ (frames 1—24)

5. Cu(OH)₂ (frames 1—24)

6. (NH₄)₂CO₃ (frames 48—56)

7. HBrO (frames 30—47)

8. H₂S (frames 25—29)

9. NaCIO₄ (frames 43—56)

10. (NH₄)₃PO₃ (frames 48—56)

11. NH₄NO₂ (frames 48—56)

12. FeI₂ (frames 1—24)

13. N₂O₃ (frames 1—24)

3. Cr = +3 since each Cl = −1; Sn = +4 since each F = −1; Fe = +3 since each O = −2 (frame 12)

4. Cu = +2 since each Cl = −1; Au = +1 since each Cl = −1; Pb = +4 since each O = −2 (frame 12)

5. Copper (I) fluoride and cuprous fluoride (frame 14)

6. Lead (IV) oxide and plumbic oxide (frame 14)

7. Hydrogen iodide and hydroiodic acid (frames 25—27)

8. Hydrogen bromide and hydrobromic acid (fames 25—27)

9. HF and HBr (frames 25—29)

10. H₂SO₄ and H₃PO₄ (frames 30—47)

11. HClO₃ = chloric acid; HBrO₃ = bromic acid; HIO₃ = iodic acid (frames 30—47)

12. HClO₄ = perchloric acid; HBrO₄ = perbromic acid; HIO₄ = periodic acid (frames 30—47)

13. HClO₂ (frames 30—47)

14. HBrO (frames 30—47)

15. Mercurous nitrate and mercury (I) nitrate (frames 12 and 14)