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Symbols and Charges for Monoatomic Ions

Fixed Charge

Symbol Name Symbol Name

H⁺ hydrogen ion H^- hydride

Li⁺ lithium ion F^- fluoride

Na⁺ sodium ion Cl^- chloride

K⁺ potassium ion Br^- bromide

Rb⁺ rubidium ion I^- iodide

Cs⁺ cesium ion O^2- oxide

Be²⁺ beryllium ion S^2- sulfide

Mg²⁺ magnesium ion Se^2- selenide

Ca²⁺ calcium ion Te^2- telluride

Sr²⁺ strontium ion N^3- nitride

Ba²⁺ barium ion P^3- phosphide

Ra²⁺ radium ion As^3- arsenide

Ag⁺ silver ion

Zn²⁺ zinc ion Al³⁺ aluminum ion

Note that the letters in an ion's name before the -ide ending is the stem.

For example, the stem for bromide is brom-. Also, just in case, the P for

phosphide is a capital P.

Symbols and Charges for Monoatomic Ions

Variable Charge

Systematic name Common Systematic name Common

Symbol (Stock system) name Symbol (Stock system) name

Cu⁺ copper(I) cuprous Hg₂²⁺ mercury(I) mercurous

Cu²⁺ copper(II) cupric Hg²⁺ mercury(II) mercuric

Fe²⁺ iron(II) ferrous Pb²⁺ lead(II) plumbous

Fe³⁺ iron(III) ferric Pb⁴⁺ lead(IV) plumbic

Sn²⁺ tin(II) stannous Co²⁺ cobalt(II) cobaltous

Sn⁴⁺ tin(IV) stannic Co³⁺ cobalt(III) cobaltic

Cr²⁺ chromium(II) chromous Ni²⁺ nickel(II) nickelous

Cr³⁺ chromium(III) chromic Ni⁴⁺ nickel(IV) nickelic

Mn²⁺ manganese(II) manganous Au⁺ gold(I) aurous

Mn³⁺ manganese(III) manganic Au³⁺ gold(III) auric

Symbols and Charges for Polyatomic Ions

Formula Name Formula Name

NO₃^- nitrate ClO₄^- perchlorate

NO₂^- nitrite ClO₃^- chlorate

CrO₄^2- chromate ClO₂^- chlorite

Cr₂O₇^2- dichromate ClO^- hypochlorite

CN^- cyanide IO₄^- periodate

MnO₄^- permanganate IO₃^- iodate

OH^- hydroxide IO^- hypoiodite

O₂^2- peroxide BrO₃^- bromate

NH₂^- amide BrO^- hypobromite

CO₃^2- carbonate HCO₃^- hydrogen carbonate (bicarbonate)

SO₄^2- sulfate HSO₄^- hydrogen sulfate (bisulfate)

SO₃^2- sulfite HSO₃^- hydrogen sulfite (bisulfite)

C₂O₄^2- oxalate HC₂O₄^- hydrogen oxalate (binoxalate)

PO₄^3- phosphate HPO₄^2- hydrogen phosphate

PO₃^3- phosphite H₂PO₄^- dihydrogen phosphate

S₂O₃^2- thiosulfate HS^- hydrogen sulfide

AsO₄^3- arsenate BO₃^3- borate

SeO₄^2- selenate B₄O₇^2- tetraborate

SiO₃^2- silicate SiF₆^2- hexafluorosilicate

C₄H₄O₆^2- tartrate

C₂H₃O₂^- acetate (an alternate way to write acetate is CH₃COO^-)

There is one positive polyatomic ion. It is NH₄⁺ and is called the ammonium ion.

Note: Writing just the plus sign or minus sign for ions with +1 or -1 charges is

acceptable.

Nomenclature Definition List

Chemical nomenclature is concerned with naming chemical compounds and writing their formulas. Gathered below are definitions of many terms used in nomenclature.

For definitions concerning bonds, see the definition list in the bonding section.

oxidation state

an alternate term that can be used when referring to the charge on an atom (but not a polyatomic ion.) There is a technical definition to this work, but it occurs later in the course. See the Redox section for more information.

metalloid

an element which has the capacity to act as either a metal or a nonmetal, depending on the chemical circumstances

nonmetal

an element that tends to gain electrons, becoming negatively charged; see anion

metal

an element that tends to lose electrons, becoming positively charged; see cation

ion

an atom or group of atoms with either a positive or a negative charge

cation

positively charged ion.

anion

negatively charged ion. The phrase "anions are negative ions" might help you to remember.

monoatomic ion

a single atom ion (mono means one) Ex: Na⁺ or Cl¯

polyatomic ion

a many atom ion (poly means many) which acts chemically as one unit. Example: NO₃¯ (1 Nitrogen atom, 3 Oxygen atoms and an extra electron giving the ion a charge of 1¯. It does not have a 3¯ charge).

ionic compound

a compound containing at least one ionic bond (contains metal(s) & nonmetal(s))

covalent compound

a compound containing only covalent bonds (covalent compounds are really molecules; contains only nonmetal atoms)

binary ionic compound

ionic compound with only 2 kinds of atoms

binary molecular compound

covalent compound with only 2 kinds of atoms

Binary Compounds of Metals with Fixed Charges

Given Formula, Write the Name

A binary compound is one made of two different elements. There can be one of each element such as in NaCl or KF. There can also be several of each element such as Na₂O or AlBr₃.

Please remember that all elements involved in this lesson have ONLY ONE charge. That includes BOTH the cation AND the anion involved in the formula.

Points to remember about naming a compound from its formula

1. The order for names in a binary compound is first the cation, then the anion.

2. Use the name of cation with a fixed oxidation state directly from the periodic table.

3. The name of the anion will be made from the root of the element's name plus the suffix "-ide."

Example 1: Write the name of the following formula: H₂S

Step #1 - Look at first element and name it. Result of this step = hydrogen.

Step #2 - Look at second element. Use root of its full name ( which is sulf-) plus the ending "-ide." Result of this step = sulfide.

These two steps give the full name of H₂S. Notice that the presence of the subscript is ignored. There are other types of binary compounds where you must pay attention to the subscript. Those compounds involve cations with variable charges. Your teacher will tell you which ones you will be held responsible for.

Example 2: Write the name of the following formula: NaCl

Step #1 - Look at first element and name it. Result of this step = sodium.

Step #2 - Look at second element. Use root of its full name ( which is chlor-) plus the ending "-ide." Result of this step = chloride.

Example 3: Write the name of the following formula: MgBr₂

Step #1 - Look at first element and name it. Result of this step = magnesium.

Step #2 - Look at second element. Use root of its full name ( which is brom-) plus the ending "-ide." Result of this step = bromide.

Note the presence of the subscript does not play a role in this name.

Example 4: Write the name of the following formula: KCl

The first part of the name comes from the first element symbol: potassium. The second part of the name comes from the root of the second symbol plus '-ide,' therefore chlor + ide = chloride.

This compound is named potassium chloride

Example 5: Write the name of the following formula: Na₂S

First symbol is Na, so the first part of the name is sodium. (Note the presence of the subscript does not play a role in this name.) Second element is sulfur (from the symbol S), so the name is sulf + ide = sulfide.

This compound is named sodium sulfide.

Three possible mistakes to be aware of:

1) Often students forget to use the suffix "-ide." For example, BaS is named "barium sulfide." An unaware student might want to name it "barium sulfur."

2) Make sure that the second name is the root plus "-ide." An unaware student might want to name BaS as "barium sulfuride." NaBr is not named sodium bromineide, the corect answer is sodium bromide.

3) There is a set of binary compounds which are named using Roman numerals. Students often confuse the two sets of rules. For example, a student might want to name Na₂S as sodium (I) sulfide. While it is never wrong to use the Roman numerals, your teacher will probably want you to only use Roman numerals on certain cations.

Here are four examples of common roots:

Cl: chlor-

F: fluor-

Br: brom-

O: ox-

Practice Problems

Write the correct name for:

Answers

1) MgS 2) KBr 3) Ba3N2 4) Al2O3 5) NaI 6) SrF2 7) Li2S 8) RaCl2 9) CaO 10) AlP 11) K2S 12) LiBr 13) Sr3P2 14) BaCl2 15) NaBr 16) MgF2 17) Na2O 18) SrS 19) BN 20) AlN 21) Cs2O 22) RbI 23) MgO 24) CaBr2 25) LiI 26) BeBr2 27) K2O 28) SrI2 29) BF3 30) Al2S3

1) magnesium sulfide 2) potassium bromide 3) barium nitride 4) aluminum oxide 5) sodium iodide 6) strontium fluoride 7) lithium sulfide 8) radium chloride 9) calcium oxide 10) aluminum phosphide 11) potassium sulfide 12) lithium bromide 13) strontium phosphide 14) barium chloride 15) sodium bromide 16) magnesium fluoride 17) sodium oxide 18) strontium sulfide 19) boron nitride 20) aluminum nitride 21) cesium oxide 22) rubidium iodide 23) magnesium oxide 24) calcium bromide 25) lithium iodide 26) berylium bromide 27) potassium oxide 28) strontium iodide 29) boron fluoride 30) aluminum sulfide

Binary Compounds of Metals with Fixed Charges

Given Name, write the formula

Example 1: Write the formula from the following name: sodium bromide

Step #1 - Write down the symbol and charge of the first word. Result = Na⁺

Step #2 - Write down the symbol and charge of the second word. Result = Br¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, only one Na⁺ and one Br¯ are required.

The resulting formula is NaBr.

Example 2: Write the formula from the following name: potassium chloride

Step #1 - Write down the symbol and charge of the first word. Result = K⁺

Step #2 - Write down the symbol and charge of the second word. Result = Cl¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, only one K⁺ and one Cl¯ are required.

The resulting formula is KCl.

Example 3: Write the formula from the following name: barium iodide

Step #1 - Write down the symbol and charge of the first word. Result = Ba²⁺

Step #2 - Write down the symbol and charge of the second word. Result = I¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, only one Ba²⁺ is required, but two I¯ are required.

Why? Answer - Two negative one charges are required because there is one postive two charge. Only in this way can the total charge of the formula be zero.

The resulting formula is BaI₂.

Example 4: Write the formula from the following name: aluminum chloride

Step #1 - Write down the symbol and charge of the first word. Result = Al³⁺

Step #2 - Write down the symbol and charge of the second word. Result = Cl¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, only one Al³⁺ is required, but three Cl¯ are required.

Why? Answer - Three negative one charges are required because there is one postive three charge. Only in this way can the total charge of the formula be zero.

The resulting formula is AlCl₃.

Example 5: Write the name of the following formula: magnesium oxide

Step #1 - Write down the symbol and charge of the first word. Result = Mg²⁺

Step #2 - Write down the symbol and charge of the second word. Result = O²¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, one Mg²⁺ is required, as well as one O²¯.

Why? Answer - One positive two charge is counterbalanced by one negative two charge. This gives a zero total charge for the formula.

The resulting formula is MgO.

Example 6: Write the name of the following formula: aluminum oxide

Step #1 - Write down the symbol and charge of the first word. Result = Al³⁺

Step #2 - Write down the symbol and charge of the second word. Result = O²¯

Step #3 - Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal zero. In this case, two Al³⁺ are required and three O²¯.

Why? Answer - This is the only possible way to get the positive and negative charges equal and keep the numbers to a minimum. Note that the positive charge is a +6 and the negative charge is a -6.

Also, keep in mind that you cannot change the charges to make a formula correct.

The resulting formula is Al₂O₃.

Warning: beware of the temptation to write the above formula as Al₃O₂.

Practice Problems

Write the correct formula for:

Answers

1) magnesium oxide 2) lithium bromide 3) calcium nitride 4) aluminum sulfide 5) potassium iodide 6) strontium chloride 7) sodium sulfide 8) radium bromide 9) magnesium sulfide 10) aluminum nitride 11) cesium sulfide 12) potassium chloride 13) strontium phosphide 14) barium iodide 15) sodium fluoride 16) calcium bromide 17) beryllium oxide 18) strontium sulfide 19) boron fluoride 20) aluminum phosphide 21) rubidium oxide 22) calcium iodide 23) cesium oxide 24) magnesium iodide 25) lithium chloride 26) beryllium bromide 27) sodium oxide 28) calcium fluoride 29) boron phosphide 30) aluminum oxide

1) MgO 2) LiBr 3) Ca3N2 4) Al2S3 5) KI 6) SrCl2 7) Na2S 8) RaBr2 9) MgS 10) AlN 11) Cs2S 12) KCl 13) Sr3P2 14) BaI2 15) NaF 16) CaBr2 17) BeO 18) SrS 19) BF3 20) AlP 21) Rb2O 22) CaI2 23) Cs2O 24) MgI2 25) LiCl 26) BeBr2 27) Na2O 28) CaF2 29) BP 30) Al2O3

Binary Compounds of Cations with Variable Charges

Given Formula, Write the Name. The Stock System

A binary compound is one made of two different elements. There can be one of each element such as in CuCl or FeO. There can also be several of each element such as Fe₂O₃ or SnBr₄.

This lesson shows you how to name binary compounds from the formula when a cation of variable charge is involved. The four formulas above are all examples of this type.

The cations involved in this lesson have AT LEAST TWO charges. The anions involved have only one charge.

The type of naming you will learn about is called the Stock system or Stock's system. It was designed by Alfred Stock (1876-1946), a German chemist and first published in 1919. In his own words, he considered the system to be "simple, clear, immediately intelligible, capable of the most general application."

In 1924, a German commission recommended Stock's system be adopted with some changes. For example, FeCl₂,which would have been named iron(2)-chloride according to Stock's original idea, became iron(II) chloride in the revised proposal. In 1934, Stock approved of the Roman numerals, but felt it better to keep the hyphen and drop the parenthesis. This suggestion has not been followed, but the Stock system remains in use world-wide.

Example #1: Write the name for: FeCl₂

Step #1 - the first part of the name is the unchanged name of the first element in the formula. In this example, it would be iron.

Step #2 - the result from step one WILL be followed by a Roman numeral. Here is how to determine its value:

1. multiply the charge of the anion (the Cl) by its subscript. Ignore the fact that it is negative. In this example it is one times two equals two.

2. divide this result by the subscript of the cation (the Fe). This is the value of the Roman numeral to use. In this example, it is two divided by one equals two.

3. The value of the Roman number equals the positive charge on the cation in this formula.

Since the result of step #2 is 2, we then use iron(II) for the name. Notice that there is no space between the name and the parenthesis.

Step #3 - the anion is named in the usual manner of stem plus "ide."

The correct name of the example is iron(II) chloride.

Example #2: name this compound: CuCl₂

In this example, I've explained it differently. Compare it to the one above. Example #4 is also explained this way.

· The first part of the name comes from the first element symbol: copper.

· The Roman numeral is II, because 2 chlorides equal -2, so the Cu must be +2. (It must be +2 so that the total charge equals zero.

· The second part of the name comes from the root of the second symbol plus 'ide,' therefore chlor + ide = chloride.

This compound is named copper(II) chloride.

Example #3: Write the name for: Fe₂O₃

Step #1 - the first part of the name is the unchanged name of the first element in the formula. In this example, it would be iron.

Step #2 - the result from step one WILL be followed by a Roman numeral. Here is how to determine its value:

1. multiply the charge of the anion (the O) by its subscript. Ignore the fact that it is negative. In this example, it is two times three equals six.

2. divide this result by the subscript of the cation (the Fe). This is the value of the Roman numeral to use. In this example, it is six divided by two equals three.

3. Note: this value of the Roman number equals the positive charge on the cation.

In this example, the result of step #2 is 3. That means that iron(III) will be used for the name. Notice that there is no space between the name and the parenthesis.

Step #3 - the anion is named in the usual manner of stem plus "ide."

The correct name of the example is iron(III) oxide.

Example #4: name this compound: SnO

· First symbol is Sn, so the first part of the name is tin.

· The Roman numeral is II, because one oxygen = -2, so the one tin equals +2.

· Second element is oxygen (from the symbol O), so the name is ox + ide = oxide.

This compound is named tin(II) oxide.

Practice Problems

Answer using the Stock system.

Write the correct name for:

Answers

1) NiS 2) PbBr4 3) Pb3N2 4) Fe2O3 5) FeI2 6) Sn3P4 7) Cu2S 8) SnCl2 9) HgO 10) Hg2F2 11) CuCl2 12) CuBr 13) PbO 14) Fe2S3 15) NiCl2 16) SnO 17) Cu2O 18) PbO2 19) NiO2 20) SnO2 21) Hg2O 22) Hg2I2 23) AuCl3 24) MnO 25) CrCl3 26) CoO 27) Mn2O3 28) Co2S3 29) AuF 30) CrBr2

1) nickel(II) sulfide 2) lead(IV) bromide 3) lead(II) nitride 4) iron(III) oxide 5) iron(II) iodide 6) tin(IV) phosphide 7) copper(I) sulfide 8) tin(II) chloride 9) mercury(II) oxide 10) mercury(I) fluoride 11) copper(II) chloride 12) copper(I) bromide 13) lead(II) oxide 14) iron(III) sulfide 15) nickel(II) chloride 16) tin(II) oxide 17) copper(I) oxide 18) lead(IV) oxide 19) nickel(IV) oxide 20) tin(IV) oxide 21) mercury(I) oxide 22) mercury(I) iodide 23) gold(III) chloride 24) manganese(II) oxide 25) chromium(III) chloride 26) cobalt(II) oxide 27) manganese(III) oxide 28) cobalt(III) sulfide 29) gold(I) fluoride 30) chromiun(II) bromide

There are Certain Formulas You Never Reduce

The most common ones are with mercury(I), which is Hg₂²⁺.

It is NEVER Hg⁺ by itself. It ALWAYS comes as a pair. There are reasons for this behavior, but that is beyond the scope of this work.

Example #1: mercury(I) chloride

The formula for this compound is Hg₂Cl₂. It is not HgCl. You will be marked wrong on a test for doing so.

Example #2: mercury(I) nitrate

The formula for this compound is Hg₂(NO₃)₂. Once again, it is not reduced. Why? In nature, mercury(I) comes in a set of two atoms, NOT just one.

The corresponding mercury(II) formula for the two examples would be HgCl₂ and Hg(NO₃)₂.

The second major category is peroxide, which is O₂²¯.

Example #3: hydrogen peroxide

The formula is H₂O₂ and it is not reduced to HO. Why? Same reason as above, peroxide travels as a group of two oxygen atoms, not one.

Example #4: sodium peroxide

The formula is Na₂O₂.

Binary Compounds of Cations with Variable Charges

Given Name, Write the Formula. The Stock System

Example #1 - Write the formula for: copper(II) chloride

Step #1 - the first word tells you the symbol of the cation. In this case it is Cu.

Step #2 - the Roman numeral WILL tell you the charge on the cation. In this case it is a positive two.

Step #3 - the anion symbol and charge comes from the second name. In this case, chloride means Cl¯.

Step #4 - remembering the rule that a formula must have zero total charge, you write the formula CuCl₂.

The ChemTeam is often asked by students, "But how do you know that chloride means Cl¯?" That type of question is usually answered with a question, as in "How do you know the name and face of your best friend?" That's right, you've spent time in their company, to the point where you have memorized the connection between name and face. Chloride is the name and Cl¯ is the face.

Example #2 - Write the formula for: copper(I) oxide

Step #1 - the first word tells you the symbol of the cation. It is Cu.

Step #2 - the Roman numeral WILL tell you the charge on the cation. It is a positive one.

Step #3 - the anion symbol and charge comes from the second name. Oxide means O²¯.

Step #4 - since a formula must have zero total charge, you write the formula Cu₂O.

Example #3 - Write the formula for: iron(III) sulfide

Step #1 - the symbol of the cation is Fe.

Step #2 - the charge on the cation is a positive three. remember, that comes from the Roman numeral.

Step #3 - Sulfide (the anion) means S²¯.

Step #4 - since a formula must have zero total charge, you write the formula Fe₂S₃.

Example #4 - Write the formula for: tin(IV) phosphide

First symbol is Sn from the name tin.

The Roman numeral IV gives +4 as tin's charge.

Phosphide give P³¯.

This compound's formula is Sn₃P₄.

This graphic summarizes example #4:

Practice Problems

Write the correct formula for:

Answers

1) iron(II) chloride 2) copper(I) sulfide 3) lead(IV) iodide 4) tin(II) fluoride 5) mercury(I) bromide 6) nickel(II) oxide 7) chromium(III) oxide 8) gold(I) iodide 9) manganese(II) nitride 10) cobalt(III) phosphide 11) iron(III) chloride 12) copper(II) sulfide 13) lead(II) bromide 14) tin(IV) iodide 15) mercury(II) fluoride 16) nickel(IV) oxide 17) manganese(III) chloride 18) chromium(II) nitride 19) gold(III) oxide 20) cobalt(II) phosphide 21) tin(II) sulfide 22) mercury(I) sulfide 23) gold(III) bromide 24) manganese(II) oxide 25) chromium(II) chloride 26) lead(IV) nitride 27) cobalt(III) oxide 28) copper(II) iodide 29) tin(IV) fluoride 30) iron(II) phosphide

1) FeCl2 2) Cu2S 3) PbI4 4) SnF2 5) Hg2Br2 6) NiO 7) Cr2O3 8) AuI 9) Mn3N2 10) CoP 11) FeCl3 12) CuS 13) PbBr2 14) SnI4 15) HgF2 16) NiO2 17) MnCl3 18) Cr3N2 19) Au2O3 20) Co3P2 21) SnS 22) Hg2S 23) AuBr3 24) MnO 25) CrCl2 26) Pb3N4 27) Co2O3 28) CuI2 29) SnF4 30) Fe3P2

Binary Compounds of Cations with Variable Charges

Common Name System

A binary compound is one made of two different elements. There can be one of each element such as in CuCl or FeO. There can also be several of each element such as Fe₂O₃ or CuBr₂.

This lesson shows you how to name binary compounds (using the common naming system) from the formula when a cation of variable charge is involved. The four formulas above are all examples of this type. Important point to remember: the cations involved in this lesson have variable charges. The anions involved have only one charge.

Antoine Laurent Lavoisier (1743-94) reformed chemistry in the late 1700's with his publication of Méthode de nomenclature chimique in 1787 (along with three co-authors) and Traité élémentaire de Chimie in 1789. He is known as the "Father of Modern Chemistry."

Two typical names of chemicals up to this point in history are "foliated earth of tartar" and "phlogisticated vitriolic acid." There were hundreds of such names. One goal of the Méthode was to create chemical names based on the chemical composition.

Lavoisier's solution, which will be studied in this lesson, was to use different suffixes to indicate differences in composition. Specifically, the use of "-ous" and "-ic" will be studied.

Here is what the IUPAC currently says about this naming system: "The following systems are in use but not recommended: The system of indicating valence by means of the suffixes -ous and -ic added to the root of the name of the cation may be retained for elements exhibiting not more than two valences."

Example #1: FeO

Step #1 - the first part of the name is the root of the first element in the formula plus a suffix. For iron the root to use is "ferr-". The suffix will be either "-ous" or "-ic."

Here is how to determine the suffix.

1. multiply the charge of the anion (the O) by its subscript. Ignore the fact that it is negative.

2. divide the result by the subscript of the cation (the Fe). This gives the positive charge on the cation.

3. the lower of the two values for a given cation is assigned the ending "-ous" and the higher uses the ending "-ic."

The result from (1) and (2) just above is two. (As you memorize the various charges, you will also internalize the above three steps.)

That last part merits a repeat: the lower of the two values will use the "-ous" ending and the higher will use "-ic." I can see you saying to yourself "How in the world do I know which one is the lower and which one is the higher?" Answer - you will know from your studies which one is lower and which is higher.

For example, iron takes on a +2 value and a +3 value. As you begin to learn these values, the question of lower and higher becomes much easier. Trust me!

Step #2 - the anion is named in the usual manner of stem plus "ide."

The answer to this example is ferrous oxide.

Example #2: Fe₂O₃

When you multiply the anion's charge (negative two) by its subscript (three) and drop the sign, you get six for an answer.

Then you divide the six by two (the iron's subscript) and you get three. This means the charge on each iron is positive three.

Since this is the higher of the two charges, the term "ferric" is used.

The answer to this example is ferric oxide.

Example #3: CuCl₂

The first part of the name comes from the first element's root: cupr-.

Two chlorides equal -2, so the Cu must be +2. "-ic" is used because +2 is the HIGHER of the two charges copper is known to have.

The second part of the name comes from the root of the second symbol plus 'ide,' therefore chlor + ide = chloride.

This compound is named cupric chloride.

Example #4: SnO

The first part of the name comes from the first element's root: stann-.

One oxygen = negative 2, so the one tin equals +2. The tin must equal +2 because you must create a formula with zero total charges. "-ous" is used because +2 is the LOWER of the two charges tin is known to have.

Second element is oxygen (from the symbol O), so the name is ox + ide = oxide.

This compound is named stannous oxide.

Practice Problems

Write the correct name for:

Answers:

1) NiS 2) PbBr4 3) Pb3N2 4) Fe2S3 5) FeI2 6) Hg2F2 7) Cu2S 8) SnCl2 9) HgO 10) Sn3P4 11) NiS2 12) PbCl2 13) Sn3N4 14) FeS 15) FeBr3 16) HgF2 17) CuS 18) SnI4 19) Hg2O 20) Pb3P4 21) NiO 22) SnO2 23) PbO2 24) Fe2O3 25) CuI 26) Hg2Cl2 27) CuO 28) Sn3N2 29) Hg2O2 30) CuCl2

1) nickelous sulfide 2) plumbic bromide 3) plumbous nitride 4) ferric sulfide 5) ferrous iodide 6) mercurous fluoride 7) cuprous sulfide 8) stannous chloride 9) mercuric oxide 10) stannic phosphide 11) nickelic sulfide 12) plumbous chloride 13) stannic nitride 14) ferrous sulfide 15) ferric bromide 16) mercuric fluoride 17) cupric sulfide 18) stannic iodide 19) mercurous oxide 20) plumbic phosphide 21) nickelous oxide 22) stannic oxide 23) plumbic oxide oxide 25) cuprous iodide 26) mercurous chloride 27) cupric oxide 28) stannous nitride 29) mercurous peroxide 30) cupric chloride

Binary Compounds of Cations with Variable Charges

Given Name, Write the Formula

Common Name System

Example #1: cuprous chloride

Step #1 - cuprous is the name of a very specific cation. It is Cu⁺ and nothing else.

I can see you saying to yourself "How in the world do I know that cuprous means Cu⁺?" Answer - you know by your studies which cation goes with which name. If you give your studies enough time, you will memorize all the names and charges, just like you have memorized many other things in your life.

Step #2 - chloride is the name of a specific anion. It is Cl¯.

Step #3 - remembering thatthe total charge of the formula must be zero, you write the formula CuCl.

Example #2: ferrous oxide

Ferrous means Fe²⁺.

Oxide means O²¯.

Following the usual rules, you write FeO for the formula.

Example #3: ferric sulfide

Ferric gives Fe³⁺.

Sulfide is S²¯.

The formula is Fe₂S₃

Keep the charge crossing technique in mind as you think about how this formula was made. Specifically, examine the aluminum oxide example.

Example #4: stannic phosphide

Stannic means Sn⁴⁺. Just like "apple" or "light bulb" mean specific things

Phosphide means P³¯.

Sn₃P₄.

Example #5: mercurous chloride

Mercurous means Hg₂²⁺

Chloride means Cl¯.

Hg₂Cl₂.

This formula is not reduced.

Practice Problems

Write the correct name for:

Answer

1) NiS 2) PbBr4 3) Pb3N2 4) Fe2S3 5) FeI2 6) Hg2F2 7) Cu2S 8) SnCl2 9) HgO 10) Sn3P4 11) NiS2 12) PbCl2 13) Sn3N4 14) FeS 15) FeBr3 16) HgF2 17) CuS 18) SnI4 19) Hg2O 20) Pb3P4 21) NiO 22) SnO2 23) PbO2 24) Fe2O3 25) CuI 26) Hg2Cl2 27) CuO 28) Sn3N2 29) Hg2O2 30) CuCl2

1) nickelous sulfide 2) plumbic bromide 3) plumbous nitride 4) ferric sulfide 5) ferrous iodide 6) mercurous fluoride 7) cuprous sulfide 8) stannous chloride 9) mercuric oxide 10) stannic phosphide 11) nickelic sulfide 12) plumbous chloride 13) stannic nitride 14) ferrous sulfide 15) ferric bromide 16) mercuric fluoride 17) cupric sulfide 18) stannic iodide 19) mercurous oxide 20) plumbic phosphide 21) nickelous oxide 22) stannic oxide 23) plumbic oxide 24) ferric oxide 25) cuprous iodide 26) mercurous chloride 27) cupric oxide 28) stannous nitride 29) mercurous peroxide 30) cupric chloride

Binary Compounds of Two Nonmetals

The Greek System

A binary compound is one made of two different elements. There can be one of each element such as in CO or NO. There can also be several of each element such as BF<SUB3 or OCl₂.

This lesson shows you how to name binary compounds from the formula when two nonmetals are involved. The four formulas above are all examples of this type. Important point to remember: NO metals (which act as the cation) are involved. That means one of the nonmetals will be acting in the positive role while the other is negative.

In fact, you do not even need to know the charges, since the formula comes right from the element names and their prefixes. Be aware that heavy use of Greek number prefixes are used in this lesson.Here are the first ten:

one mono- six hexa-

two di- seven hepta-

three tri- eight octa-

four tetra- nine nona-

five penta- ten deca-

Example #1 - write the name for N₂O.

Example #2 - write the name for NO₂.

Step #1 - part of the first name is the unchanged name of the first element in the formula. In the examples above, it would be nitrogen.

If the subscript of the first element is 2 or more, you add a prefix to the name. In the first example above, you would write dinitrogen. If the subscript is one as in the second example above, you DO NOT use a prefix. You simply write the name, in this example it would be nitrogen.

Step #2 - the anion is named in the usual manner of stem plus "ide." In addition, a prefix is added. In the first example, the prefix is "mono-" since there is one oxygen. In the second example, use "di-" because of two oxygens.

The correct names of the two examples are dinitrogen monoxide and nitrogen dioxide.

Note that "monoxide" is written rather than "monooxide." It sounds better when spoken out loud.

Example #3 - write the name for IF₇.

Step #1 - the first element is iodine and there is only one. This part of the name will be "iodine", NOT "monoiodine."

Step #2 - the second element is fluorine, so "fluoride" is used. Since there are seven, the prefix "hepta" is used.

The name of this compound is iodine heptafluoride.

Example #4 - write the name for N₂O₅.

Step #1 - the first element is nitrogen and there are two. This part of the name will be "dinitrogen."

Step #2 - the second element is oxygen, so "oxide" is used. Since there are five, the prefix "penta" is used.

The name of this compound is "dinitrogen pentaoxide." Many write is as "dinitrogen pentoxide." The ChemTeam believes that both are considered correct, but the second is to be prefered.

Example #5 - write the name for XeF₂.

The first part of the name comes from the first element's name: xenon. Since there is only one atom present, no prefix is used.

The second part of the name comes from the root of the second symbol plus 'ide' as well as the prefix "di-,"therefore di + fluor + ide = difluoride.

This compound is named xenon difluoride.

Example #6 - write the name for N₂O₄.

The first part of the name comes from the first element's name: nitrogen. Since there are two atoms, the prefix "di-" is used giving dinitrogen.

The second part of the name comes from the root of the second symbol plus 'ide' as well as the prefix "tetra-,"therefore tetr + ox + ide = tetroxide.

This compound is named dinitrogen tetroxide. Notice the dropping of the "a" in tetra.

Just a reminder: this system of naming does not really have an offically accepted name, but is often called the Greek system (or method). It involves use of Greek prefixes when naming binary compounds of two nonmetals.

Sometimes you will see the Stock system applied to these types of compounds. Here is what the IUPAC currently says about that practice: "The Stock notation can be applied to both cations and anions, but preferably should not be applied to compounds between nonmetals."

Practice Problems

Write the correct name for:

Answers:

1) As4O10 2) BrO3 3) BN 4) N2O3 5) NI3 6) SF6 7) XeF4 8) PCl3 9) CO 10) PCl5 11) P2O5 12) S2Cl2 13) ICl2 14) SO2 15) P4O10 16) UF6 17) OF2 18) ClO2 19) SiO2 20) BF3 21) N2S5 22) CO2 23) SO3 24) XeF6 25) KrF2 26) BrCl5 27) SCl4 28) PF3 29) XeO3 30) OsO4

1) tetrarsenic decoxide 2) bromine trioxide 3) boron nitride 4) dinitrogen trioxide 5) nitrogen triiodide 6) sulfur hexafluoride 7) xenon tetrafluoride 8) phosphorous trichloride 9) carbon monoxide 10) phosphorous pentachloride 11) diphosphorous pentoxide 12) disulfur dichloride 13) iodine dichloride 14) sulfur dioxide 15) tetraphosphorous decoxide 16) uranium hexafluoride 17) oxygen difluoride 18) chlorine dioxide 19) silicon dioxide 20) boron trifluoride 21) dinitrogen pentasulfide 22) carbon dioxide 23) sulfur trioxide 24) xenon hexafluoride 25) krypton difluoride 26) bromine pentachloride 27) sulfur tetrachloride 28) phosphorous trifluoride 29) xenon trioxide 30) osmium tetroxide

Compounds Involving a Polyatomic Ion

These compounds to follow ARE NOT binary compounds. They contain three or more elements, as opposed to only two in a binary compound.

The Greek method WILL NOT be used. That naming technique is used only for binary compounds of two nonmetals. That means, if you see a formula like BaSO₄, the name is not barium monosulfur tetraoxide. Many unaware ChemTeam students over the years have made this error and suffered for it.

Consequently, a warning: it is important that you learn to recognize the presence of a polyatomic ion in a formula. Many ChemTeam students have made it their first priority to make a set of flashcards with the name on one side and the ion and its charge on the other. Then, carry them everywhere and use them.

The cations used will be a mix of fixed charges AND variable charges. You must know which are which.

Another warning: you must also know the charges associated with each polyatomic ion. For example, NO₃¯ is called nitrate and it has a minus one charge. Once again, many unaware ChemTeam students have thought this means nitrate has a minus three charge. IT DOES NOT.

Use of Parenthesis

When more than one polyatomic ion is required, parenthesis are used to enclose the ion with the subscript going outside the parenthesis. For example, the very first formula used is Fe(NO₃)₂. This means that two NO₃¯ are involved in the compound. Without the parenthesis, the formula would be FeNO₃₂, a far cry from the correct formula.

When you say a formula involving parenthesis out loud, you use the word "taken" as in the formula for ammonium sulfide, which is (NH₄)₂S. Out loud, you say "N H four taken twice S." OR with the formula for copper(II) chlorate, which is Cu(ClO₃)₂. You say " Cu Cl O three taken twice."

Example #1 - write the name for Fe(NO₃)₂

Step #1 - decide if the cation is one showing variable charge. If so, a Roman numeral will be needed. In this case, iron does show variable charge.

If a variable charge cation is involved, you must determine the Roman numeral involved. You do this by computing the total charge contributed by the polyatomic ion. In this case, NO₃¯ has a minus one charge and there are two of them, making a total of minus 2.

Therefore, the iron must be a positive two, in order to keep the total charge of the formula at zero.

Step #2 - determine the name of the polyatomic ion. Nitrate is the name of NO₃¯.

The correct name is iron(II) nitrate. The common name would be ferrous nitrate.

Example #2 - write the name for NaOH

Step #1 - the cation, Na⁺, does not show a variable charge, so no Roman numeral is needed. The name is sodium.

Step#2 - OH¯ is recognized as the hydroxide ion.

The name of this compound is sodium hydroxide.

Usually, at this point, a cry is heard in the ChemTeam's classroom. "But how do you know that OH¯ is hydroxide?" is the plaintive wail. The stock ChemTeam answer is "Well, how do you know anything? How do you know your phone number? How do you know your best friend's name? In fact, how do you know your name?" There are three things you must memorize: the name (hydroxide), the symbol (OH) and the charge (minus one). You must put in the time to learn this nomenclature stuff. It does not come easy and the ChemTeam realizes you'd rather be spending the time doing more important things: going cool places with friends, spending time with members of the opposite sex, spending your parents' money, sleeping, etc. Maybe some other time. Right now, let's move on.

Example #3 - write the name for KMnO₄

Step #1 - the cation, K⁺, does not show a variable charge, so no Roman numeral is needed. The name is potassium.

Step#2 - MnO₄¯ is recognized as the permanganate ion.

The name of this compound is potassium permanganate.

Example #4 - write the name for Cu₂SO₄

Step #1 - decide if the cation is one showing variable charge. If so, a Roman numeral will be needed. In this case, copper does show variable charge.

If a variable charge cation is involved, you must determine the Roman numeral involved. You do this by computing the total charge contributed by the polyatomic ion. In this case, SO₄²¯ has a minus two charge and there is only one, making a total of minus 2.

Therefore, the copper must be a positive one. Why? Well, there must be a positive two to go with the negative two in order to make zero. Since the formula shows two copper atoms involved, each must be a plus one charge.

Step #2 - determine the name of the polyatomic ion. Sulfate is the name of SO₄²¯.

The correct name is copper(I) sulfate. The common name would be cuprous sulfate.

Practice Problems

Write the correct name for:

Answers:

1) AlPO4 2) KNO2 3) NaHCO3 4) CaCO3 5) Mg(OH)2 6) Na2CrO4 7) Ba(CN)2 8) K2SO4 9) NaH2PO4 10) NH4NO3 11) Sn(NO3)2 12) FePO4 13) Cu2SO4 14) Ni(C2H3O2)2 15) HgCO3 16) Pb(OH)4 17) Cu2Cr2O7 18) Cu(ClO3)2 19) FeSO4 20) Hg2(ClO4)2 21) KClO3 22) SnSO4 23) Al(MnO4)3 24) Pb(NO3)2 25) Mg3(PO4)2 26) CuH2PO4 27) CaHPO4 28) Fe(HCO3)3 29) Na2CO3 30) MnSO4

1) aluminum phosphate 2) potassium nitrite 3) sodium hydrogen carbonate [sodium bicarbonate] 4) calcium carbonate 5) magnesium hydroxide 6) sodium cromate 7) barium cyanide 8) potassium sulfate 9) sodium dihydrogen phosphate 10) ammonium nitrate 11) tin(II) nitrate [stannous nitrate] 12) iron(III) phosphate [ferric phosphate] 13) copper(II) sulfate [cupric sulfate] 14) nickel(II) acetate [nickelous acetate] 15) mercury(II) carbonate [mercuric carbonate] 16) lead(IV) hydroxide [plumbic hydroxide] 17) copper(I) dichromate [cuprous dichromate] 18) copper(II) chlorate [cupric chlorate] 19) iron(II) sulfate [ferrous sulfate] 20) mercury(I) perchlorate [mercurous perchlorate] 21) potassium chlorate 22) tin(II) sulfate [stannous sulfate] 23) aluminum permanganate 24) lead(II) nitrate [plumbous nitrate] 25) magnesium phosphate 26) copper(I) dihydrogen phosphate 27) calcium hydrogen phosphate 28) iron(III) hydrogen carbonate 29) sodium carbonate 30) manganese(II) sulfate [manganous sulfate]

Nomenclature of Inorganic Acids

Recognizing an Acid

At this very beginning level, you will recognize an acid by the fact that its formula starts with H, as in these examples:

HCl
HNO₃
H₂SO₄
HClO₃
H₃BO₃

As you become more sophisticated in your chemistry, you will realize that there are many acid formulas that do not start with H, but those will almost all be left for another time.

There is one exception to this: the formula CH₃COOH should be recognized as acetic acid. The particular way it is written is common in organic chemistry. An alternate way to write acetic acid is HC₂H₃O₂. This is done in the inorganic style which you are currently studying.

One last comment before looking at how to name acids: the formula H₂O should not be considered an acid. It is the formula for water. It is not an acid. When you study acid-base behavior later in the school year, you will learn more about water's role in acid-base chemistry, but not now.

Naming Acids

In order to explain acid naming, the sequence of HCl, HClO, HClO₂, HClO₃, and HClO₄ will be discussed in order.

HCl is a binary acid. All binary acids are named the same way:

1. the prefix "hydro" is used.

2. the root of the anion is used.

3. the suffix "ic" is used.

4. the word "acid" is used as the second word in the name.

The name for HCl is hydrochloric acid. Other binary acids you are responsible for are HF, HBr, HI, and H₂S.

1) HClO is an acid involving a polyatomic ion. You MUST recognize the polyatomic ion in the formula. There is no other way to figure out the name. If you don't recognize the polyatomic, then you're sunk without a trace.

The polyatomic ion is ClO¯ and its name is hypochlorite. Any time you see the "ite" suffic, you change it to "ous" and add the word acid.

The name of HClO is hypochlorous acid.

2) HClO₂ has the ClO₂¯ polyatomic ion in it. The name of this ion is chlorite.

Since the "ite" suffix is used, it gets changed to "ous."

The name of HClO₂ is chlorous acid.

3) HClO₃ has the ClO₃¯ polyatomic ion and its name is chlorate. Any time you know the "ate" ending is used on the polyatomic, you use "ic" when its an acid.

The name of HClO₃ is chloric acid.

4) HClO₄ has the ClO₄¯ polyatomic ion and its name is perchlorate.

Since the "ate" suffix is used, it gets changed to "ic."

The name of HClO₄ is perchloric acid.

In the ChemTeam's estimation there are two keys. You have to:

1. recognize when a polyatomic is present and

2. know its name.

Only then can you know to change the "ite" suffix to "ous" and the "ate" suffix to "ic" when it is an acid.

Practice Problems

1) H3PO4 2) H2CO3 3) H2SO4 4) HIO3 5) HF 6) HNO2 Write the formula for these acids: 7) hydrobromic acid 8) hydrocyanic acid 9) nitric acid 10) sulfurous acid 11) phosphorous acid 12) acetic acid 1) H3PO3 2) HClO3 3) H2SO3 4) HBrO3 5) HI 6) CH3COOH Write the formula for these acids: 7) hydrochloric acid 8) hydrosulfic acid [this has a twist in it] 9) perchloric acid 10) hydrogen hydroxide

1) phosphoric acid 2) carbonic acid 3) sulfuric acid 4) iodic acid 5) hydrofluoric acid 6) nitrous acid 7) HBr 8) HCN 9) HNO3 10) H2SO3 11) H3PO3 12) CH3COOH or HC2H3O2 1) phosphorous acid 2) chloric acid 3) sulfurous acid 4) bromic acid 5) hydroiodic acid (not hydroidiotic acid!) 6) acetic acid 7) HCl 8) H2S 9) HClO4 10) HOH (more usually know as H2O or water)

1. ammonium sulfide 26. nickel(II) iodide

2. sodium nitrate 27. mercurous oxide

3. cupric bromide 28. lead(II) chlorite

4. aluminum sulfate 29. hydrogen iodide

5. potassium nitrate 30. iron(II) bisulfite

6. ferrous carbonate 31. magnesium nitrate

7. lead(II) phosphate 32. iron(III) chromate

8. diphosphorus pentoxide 33. iron(II) chromate

9. cupric hydroxide 34. copper(II) hydroxide

10. calcium fluoride 35. cuprous carbonate

11. nickel(II) nitrate 36. chromic acetate

12. silver cyanide 37. calcium chlorate

13. ammonium sulfite 38. ammonium oxide

14. zinc sulfate 39. aluminum perchlorate

15. tin(II) chloride 40. zinc bicarbonate

16. antimony(III) chloride 41. sodium phosphate

17. silver sulfide 42. silver hypochlorite

18. magnesium hydroxide 43. ammonium phosphate

19. ammonium carbonate 44. ferrous chlorite

20. nickel(II) acetate 45. potassium sulfide

21. sodium chromate 46. tin(IV) bromide

22. chromic bisulfate 47. lithium chromate

23. potassium permanganate 48. magnesium bisulfate

24. silver perchlorate 49. ferrous phosphate

25. potassium phosphate 50. calcium sulfate dihydrate

51. aluminum acetate 76. lithium hypochlorite

52. calcium chloride dihydrate 77. oxygen difluoride

53. barium chromate 78. cobalt(II) hydrogen sulfate

54. cobaltic chloride 79. acetic acid (see #128)

55. barium chloride dihydrate 80. barium hypochlorite

56. sulfurous acid 81. ammonium hydroxide

57. potassium hydroxide 82. cobalt(II) iodide

58. zinc bisulfite 83. chromium(II) bicarbonate

59. sodium sulfite 84. sodium hydroxide

60. cobaltous sulfate 85. silver nitrate

61. ferric oxide 86. mercury(II) nitrate

62. silver phosphate 87. hydrochloric acid

63. sodium hypochlorite 88. aluminum bisulfite

64. ammonium chromate 89. cobalt(III) hydrogen sulfate

65. barium carbonate 90. ferric hydrogen carbonate

66. calcium iodide 91. phosphorus pentabromide

67. cupric sulfate 92. nickel(II) chloride hexahydrate

68. cuprous chloride 93. ammonium aluminum sulfate

69. ferric carbonate 94. iron(III) hydrogen carbonate

70. zinc phosphate 95. mercury(I) hydrogen phosphate

71. sodium nitrite 96. plumbic hydrogen carbonate

72. silver oxide 97. mercuric hydrogen carbonate

73. nickel(II) bromide 98. mercurous hydrogen phosphate

74. magnesium oxide 99. copper(II) sulfate pentahydrate

75. mercuric perchlorate 100. chromic dihydrogen phosphate

1. (NH₄)₂S 26. NiI₂

2. NaNO₃ 27. Hg₂O

3. CuBr₂ 28. Pb(ClO₂)₂

4. Al₂(SO₄)₃ 29. HI

5. KNO₃ 30. Fe(HSO₃)₂

6. FeCO₃ 31. Mg(NO₃)₂

7. Pb₃(PO₄)₂ 32. Fe₂(CrO₄)₃

8. P₂O₅ 33. FeCrO₄

9. Cu(OH)₂ 34. Cu(OH)₂

10. CaF₂ 35. Cu₂CO₃

11. Ni(NO₃)₂ 36. Cr(C₂H₃O₂)₃

12. AgCN 37. Ca(ClO₃)₂

13. (NH₄)₂SO₃ 38. (NH₄)₂O

14. ZnSO₄ 39. Al(ClO₄)₃

15. SnCl₂ 40. Zn(HCO₃)₂

16. SbCl₃ 41. Na₃PO₄

17. Ag₂S 42. AgClO

18. Mg(OH)₂ 43. (NH₄)₃PO₄

19. (NH₄)₂CO₃ 44. Fe(ClO₂)₂

20. Ni(C₂H₃O₂)₂ 45. K₂S

21. Na₂CrO₄ 46. SnBr₄

22. Cr(HSO₄)₃ 47. Li₂CrO₄

23. KMnO₄ 48. Mg(HSO₄)₂

24. AgClO₄ 49. Fe₃(PO₄)₂

25. K₃PO₄ 50. CaSO₄^.2H₂O

51. Al(C₂H₃O₂)₃ 76. LiClO

52. CaCl₂^.2H₂O 77. OF₂

53. BaCrO₄ 78. Co(HSO₄)₂

54. CoCl₃ 79. CH₃COOH

55. BaCl₂^.2H₂O 80. Ba(ClO)₂

56. H₂SO₃ 81. NH₄OH

57. KOH 82. CoI₂

58. Zn(HSO₃)₂ 83. Cr(HCO₃)₂

59. Na₂SO₃ 84. NaOH

60. CoSO₄ 85. AgNO₃

61. Fe₂O₃ 86. Hg(NO₃)₂

62. Ag₃PO₄ 87. HCl

63. NaClO 88. Al(HSO₃)₃

64. (NH₄)₂CrO₄ 89. Co(HSO₄)₃

65. BaCO₃ 90. Fe(HCO₃)₃

66. CaI₂ 91. PBr₅

67. CuSO₄ 92. NiCl₂^.6H₂O

68. CuCl 93. NH₄Al(SO₄)₂

69. Fe₂(CO₃)₃ 94. Fe(HCO₃)₃

70. Zn₃(PO₄)₂ 95. Hg₂HPO₄

71. NaNO₂ 96. Pb(HCO₃)₄

72. Ag₂O 97. Hg(HCO₃)₂

73. NiBr₂ 98. Hg₂HPO₄

74. MgO 99. CuSO₄^.5H₂O

75. Hg(ClO₄)₂ 100. Cr(H₂PO₄)₃