naming compounds

Naming Naming compoundscompoundsChapter 7 review for retestChapter 7 review for retest

Cation namingCation naming

Monatomic Cation Names Monatomic Cation Names The names of monatomic cations always start with the The names of monatomic cations always start with the

name of the metal, sometimes followed by a Roman name of the metal, sometimes followed by a Roman numeral to indicate the charge of the ion. For example, numeral to indicate the charge of the ion. For example, Cu+ is copper(I), and Cu2+ is copper(II). The Roman Cu+ is copper(I), and Cu2+ is copper(II). The Roman numeral in each name represents the charge on the numeral in each name represents the charge on the ion and allows us to distinguish between more than one ion and allows us to distinguish between more than one possible charge. Notice that there is no space between possible charge. Notice that there is no space between the end of the name of the metal and the parentheses the end of the name of the metal and the parentheses with the Roman numeral. with the Roman numeral.


If the atoms of an element always have the If the atoms of an element always have the same charge, the Roman numeral is same charge, the Roman numeral is unnecessary (and considered to be incorrect). unnecessary (and considered to be incorrect). For example, all cations formed from sodium For example, all cations formed from sodium atoms have a +1 charge, so Na+ is named atoms have a +1 charge, so Na+ is named sodium ion, without the Roman numeral for the sodium ion, without the Roman numeral for the charge. The following elements have only one charge. The following elements have only one possible charge, so it would be incorrect to put possible charge, so it would be incorrect to put a Roman numeral after their name. a Roman numeral after their name.


The alkali metals in group 1 are always The alkali metals in group 1 are always +1 when they form cations. +1 when they form cations.

The alkaline earth metals in group 2 are The alkaline earth metals in group 2 are always +2 when they form cations. always +2 when they form cations.

Aluminum and the elements in group 3 Aluminum and the elements in group 3 are always +3 when they form cations. are always +3 when they form cations.

Zinc and cadmium always form +2 Zinc and cadmium always form +2 cations. cations.


Although silver can form both +1 and +2 Although silver can form both +1 and +2 cations, the +2 is so rare that we usually cations, the +2 is so rare that we usually name Ag+ as name Ag+ as silver ionsilver ion, not , not silver(I) ion.silver(I) ion. Ag2+ is named silver(II) ion. Ag2+ is named silver(II) ion.


We will assume that all of the metallic We will assume that all of the metallic elements other than those mentioned elements other than those mentioned above can have more than one charge, above can have more than one charge, so their cation names will include a so their cation names will include a Roman numeral. For example, Mn2+ is Roman numeral. For example, Mn2+ is named manganese(II). We know to put named manganese(II). We know to put the Roman numeral in the name because the Roman numeral in the name because manganese is not on our list of metals manganese is not on our list of metals with only one charge. with only one charge.

Anion namingAnion naming

Monatomic Anion Names Monatomic Anion Names The monatomic anions are named by The monatomic anions are named by

adding -ide to the root of the name of the adding -ide to the root of the name of the nonmetal that forms the anion. For nonmetal that forms the anion. For example, N3- is the nitride ion. The example, N3- is the nitride ion. The names of the anions are below . names of the anions are below .


hydride ion, H- hydride ion, H- nitride ion, N3- nitride ion, N3- phosphide ion, P3- phosphide ion, P3- oxide ion, O2- oxide ion, O2- sulfide ion, S2- sulfide ion, S2- selenide ion, Se2- selenide ion, Se2- fluoride ion, F- fluoride ion, F- chloride ion, Cl- chloride ion, Cl- bromide ion, Br- bromide ion, Br- iodide ion, I- iodide ion, I-


Polyatomic Anion Names Polyatomic Anion Names There is many polyatomic anions. The There is many polyatomic anions. The

following anions are most common.following anions are most common. hydroxide ion, OH- hydroxide ion, OH- nitrate ion, NO3- nitrate ion, NO3- acetate ion, C2H3O2- acetate ion, C2H3O2- carbonate ion, CO32- carbonate ion, CO32- sulfate ion, SO42- sulfate ion, SO42- phosphate ion, PO43- phosphate ion, PO43-


Some polyatomic anions are formed by the attachment Some polyatomic anions are formed by the attachment of one or more hydrogen atoms. In fact, it is common of one or more hydrogen atoms. In fact, it is common for hydrogen atoms to be transferred from one ion or for hydrogen atoms to be transferred from one ion or molecule to another ion or molecule. When this molecule to another ion or molecule. When this happens, the hydrogen atom is usually transferred happens, the hydrogen atom is usually transferred without its electron, as H+. If an anion has a charge of -without its electron, as H+. If an anion has a charge of -2 or -3, it can gain one or two H+ ions and still retain a 2 or -3, it can gain one or two H+ ions and still retain a negative charge. For example, carbonate, CO32-, can negative charge. For example, carbonate, CO32-, can gain an H+ ion to form HCO3-, which is found in baking gain an H+ ion to form HCO3-, which is found in baking soda. The sulfide ion, S2-, can gain one H+ ion to form soda. The sulfide ion, S2-, can gain one H+ ion to form HS-. HS-.


Phosphate, PO43-, can gain one H+ ion Phosphate, PO43-, can gain one H+ ion and form HPO42-, or it can gain two H+ and form HPO42-, or it can gain two H+ ions to form H2PO4-. These polyatomic ions to form H2PO4-. These polyatomic ions are named with the word ions are named with the word hydrogenhydrogen in front of the name of the anion if there in front of the name of the anion if there is one H+ ion attached and is one H+ ion attached and dihydrogendihydrogen in in front of the name of the anion if two H+ front of the name of the anion if two H+ ions are attached. ions are attached.


HCO3- is hydrogen carbonate ion. HCO3- is hydrogen carbonate ion. HS- is hydrogen sulfide ion. HS- is hydrogen sulfide ion. HPO42- is hydrogen phosphate ion. HPO42- is hydrogen phosphate ion. H2PO4- is dihydrogen phosphate ion.H2PO4- is dihydrogen phosphate ion. Some polyatomic ions also have nonsystematic Some polyatomic ions also have nonsystematic

names that are often used. For example, names that are often used. For example, HCO3– is often called bicarbonate instead of HCO3– is often called bicarbonate instead of hydrogen carbonate. You should avoid using hydrogen carbonate. You should avoid using this less accepted name, but because many this less accepted name, but because many people still use it, you should know it. people still use it, you should know it.

Ionic compoundsIonic compounds

Metal‑nonmetal:Metal‑nonmetal: Ionic compounds whose Ionic compounds whose formula contains one symbol for a metal and formula contains one symbol for a metal and one symbol for a nonmetal are called binary one symbol for a nonmetal are called binary ionic compounds. Their general formula is ionic compounds. Their general formula is MaAb, with “M” representing the symbol of a MaAb, with “M” representing the symbol of a metallic element, “A” representing the symbol metallic element, “A” representing the symbol for a nonmetallic element, and lowercase “a” for a nonmetallic element, and lowercase “a” and “b” representing subscripts in the formula and “b” representing subscripts in the formula (unless one or more of the subscripts are (unless one or more of the subscripts are assumed to be 1). assumed to be 1).


For example, NaF (used to fluoridate For example, NaF (used to fluoridate municipal waters), MgCl2 (used in floor municipal waters), MgCl2 (used in floor sweeping compounds), and Al2O3 (in sweeping compounds), and Al2O3 (in ceramic glazes) represent binary ionic ceramic glazes) represent binary ionic compounds. compounds.


Metal‑polyatomic ion:Metal‑polyatomic ion: Polyatomic ions Polyatomic ions can take the place of monatomic anions, can take the place of monatomic anions, so formulas that contain a symbol for a so formulas that contain a symbol for a metallic element and the formula for a metallic element and the formula for a polyatomic ion represent ionic polyatomic ion represent ionic compounds. For example, NaNO3 (in compounds. For example, NaNO3 (in solid rocket propellants) and Al2(SO4)3 solid rocket propellants) and Al2(SO4)3 (a foaming agent in fire foams) represent (a foaming agent in fire foams) represent ionic compounds. ionic compounds.


Ammonium‑nonmetal or Ammonium‑nonmetal or ammonium‑polyatomic ion:ammonium‑polyatomic ion: Ammonium Ammonium ions, NH4+, can take the place of metallic ions, NH4+, can take the place of metallic cations in an ionic compound, so cations in an ionic compound, so chemical formulas that contain the chemical formulas that contain the formula for ammonium with either a formula for ammonium with either a symbol for a nonmetallic element or a symbol for a nonmetallic element or a formula for a polyatomic ion represent formula for a polyatomic ion represent ionic compounds. ionic compounds.


Cations are named in one of the following Cations are named in one of the following ways. ways.

name of metalname of metal...for the metallic elements in ...for the metallic elements in Groups 1, 2, and 3 and for Al3+, Zn2+, Cd2+, Groups 1, 2, and 3 and for Al3+, Zn2+, Cd2+, and Ag+. and Ag+.

name of metal(Roman numeral)name of metal(Roman numeral)...for the ...for the other metallic elements. other metallic elements.

name of polyatomic ionname of polyatomic ion...the ammonium ion, ...the ammonium ion, NH4+, is the only common polyatomic cation. NH4+, is the only common polyatomic cation.


Anions are named in one of the following Anions are named in one of the following ways. ways.

(root of the name of a (root of the name of a nonmetal)idenonmetal)ide...for monatomic anions. ...for monatomic anions.

name of polyatomic ionname of polyatomic ion


Converting Names to Formulas Converting Names to Formulas Before you can write a chemical formula from the name Before you can write a chemical formula from the name

of a compound, you need to recognize what type of of a compound, you need to recognize what type of compound the name represents. For binary ionic compound the name represents. For binary ionic compounds, the first part of the name is the name of a compounds, the first part of the name is the name of a metallic cation. This may include a Roman numeral in metallic cation. This may include a Roman numeral in parentheses. The anion name starts with the root of the parentheses. The anion name starts with the root of the name of a nonmetal and ends with name of a nonmetal and ends with ‑ide‑ide. .

(name of metal)(maybe Roman numeral) (root of (name of metal)(maybe Roman numeral) (root of nonmetal)idenonmetal)ide


You can identify other names as representing You can identify other names as representing ionic compounds by recognizing that they ionic compounds by recognizing that they contain the names of common polyatomic ions. contain the names of common polyatomic ions. For example, ammonium chloride and iron(III) For example, ammonium chloride and iron(III) hydroxide are both ionic compounds. Many of hydroxide are both ionic compounds. Many of the polyatomic ions that you will be expected to the polyatomic ions that you will be expected to recognize end in recognize end in ‑ate‑ate, so this ending tells you , so this ending tells you that the name represents an ionic compound. that the name represents an ionic compound. Copper(II) sulfate is an ionic compound. Copper(II) sulfate is an ionic compound.


Follow these steps to write formulas for Follow these steps to write formulas for ionic compounds. ionic compounds.

Step 1:Step 1: Write the formula, including the Write the formula, including the charge, for the cation. charge, for the cation.

Step 2: Step 2: Write the formula, including the Write the formula, including the charge, for the anion. charge, for the anion.


Step 3:Step 3: Write subscripts for each formula Write subscripts for each formula so as to yield an uncharged compound. so as to yield an uncharged compound. ( Use the lowest whole number ratio for ( Use the lowest whole number ratio for the subscripts. If the subscript for a the subscripts. If the subscript for a polyatomic ion is higher than one, place polyatomic ion is higher than one, place the formula for the polyatomic ion in the formula for the polyatomic ion in parentheses and put the subscript parentheses and put the subscript outside the parentheses.) outside the parentheses.)

Binary Covalent namingBinary Covalent naming

Systematic Names Systematic Names You can recognize binary covalent compounds from You can recognize binary covalent compounds from

their formulas, which contain symbols for only two, their formulas, which contain symbols for only two, nonmetallic elements. The general pattern of such nonmetallic elements. The general pattern of such formulas is AaBb, where “A” and “B” represent symbols formulas is AaBb, where “A” and “B” represent symbols for nonmetals, and “a” and “b” represent subscripts for nonmetals, and “a” and “b” represent subscripts (remember that if one of the subscripts is absent, it is (remember that if one of the subscripts is absent, it is understood to be 1). For example, because nitrogen understood to be 1). For example, because nitrogen and oxygen are nonmetallic elements, the formula and oxygen are nonmetallic elements, the formula N2O3 represents a binary covalent compound. N2O3 represents a binary covalent compound.


Follow these steps to write the names for binary Follow these steps to write the names for binary covalent compounds. covalent compounds.

If the subscript for the first element is greater than If the subscript for the first element is greater than one, indicate the identity of the subscript using one one, indicate the identity of the subscript using one of the prefixes listed below .of the prefixes listed below . We do not write mono- We do not write mono- at the beginning of a compound’s name. at the beginning of a compound’s name.

Example:Example: We start the name for N2O3 with We start the name for N2O3 with di-di-.. Attach the selected prefix to the name of the first Attach the selected prefix to the name of the first

element in the formula. If no prefix is to be used, element in the formula. If no prefix is to be used, begin with the name of the first element.begin with the name of the first element.

Example: Example: We indicate the N2 portion of N2O3 with We indicate the N2 portion of N2O3 with dinitrogendinitrogen. .


Select a prefix to identify the subscript for Select a prefix to identify the subscript for the second element (even if its subscript is the second element (even if its subscript is understood to be one). understood to be one). Leave the "a" off the Leave the "a" off the end of the prefixes that end in "a" and the “o” end of the prefixes that end in "a" and the “o” off of mono‑ if they are placed in front of an off of mono‑ if they are placed in front of an element whose name begins with a vowel element whose name begins with a vowel (oxygen or iodine).(oxygen or iodine).

Example:Example: The name of N2O3 grows to The name of N2O3 grows to dinitrogen trioxidedinitrogen trioxide


Write the root of the name of the Write the root of the name of the second element in the formula as second element in the formula as shown below. shown below.

Example:Example: The name of N2O3 becomes The name of N2O3 becomes dinitrogen triox-.dinitrogen triox-.

Add -ide to the end of the name.Add -ide to the end of the name. Example: Example: The name of N2O3 is The name of N2O3 is

dinitrogen trioxide.dinitrogen trioxide.


Converting Names to Formulas Converting Names to Formulas The first step in writing formulas when given the The first step in writing formulas when given the

systematic name of a binary covalent compound is to systematic name of a binary covalent compound is to recognize the name as representing a binary covalent recognize the name as representing a binary covalent compound. It will have one of the following general compound. It will have one of the following general forms.forms.

prefix (name of nonmetal) prefix (root of name of prefix (name of nonmetal) prefix (root of name of nonmetal)ide nonmetal)ide (e.g. dinitrogen pentoxide)(e.g. dinitrogen pentoxide)

or or (name of nonmetal) prefix (root of name of (name of nonmetal) prefix (root of name of nonmetal) ide nonmetal) ide (e.g. carbon dioxide)(e.g. carbon dioxide)

or or (name of nonmetal) (root of nonmetal) ide (name of nonmetal) (root of nonmetal) ide (e.g. (e.g. hydrogen fluoride)hydrogen fluoride)


Follow these steps for writing formulas for binary Follow these steps for writing formulas for binary covalent compounds when you are given a systematic covalent compounds when you are given a systematic name. Notice that they are the reverse of the steps for name. Notice that they are the reverse of the steps for writing names from chemical formulas.writing names from chemical formulas.

Write the symbols for the elements in the order Write the symbols for the elements in the order mentioned in the name. mentioned in the name.

Write subscripts indicated by the prefixes. If the Write subscripts indicated by the prefixes. If the first part of the name has no prefix, assume it is first part of the name has no prefix, assume it is mono-.mono-.

Remember that HF, HCl, HBr, HI, and H2S are often Remember that HF, HCl, HBr, HI, and H2S are often named without prefixes. You will also be expected to named without prefixes. You will also be expected to write formulas for the compounds whose write formulas for the compounds whose nonsystematic names are listed above. nonsystematic names are listed above.


Binary Covalent NomenclatureBinary Covalent Nomenclature The purpose of this page is to describe the The purpose of this page is to describe the

guidelines for constructing the names for guidelines for constructing the names for binary covalent compounds, which are pure binary covalent compounds, which are pure substances that consist of two nonmetallic substances that consist of two nonmetallic elements. The water, H2O, you boil to cook elements. The water, H2O, you boil to cook your potatoes and the methane, CH4, in your potatoes and the methane, CH4, in natural gas that can be burned to heat the natural gas that can be burned to heat the water are examples of binary covalent water are examples of binary covalent compounds.compounds.

Traditional system of Traditional system of namingnaming

Makes use of suffixesMakes use of suffixes The suffix –ous is added to the latin root The suffix –ous is added to the latin root

of the metallic ion that has the lower of the metallic ion that has the lower charge.charge.

The suffix –ic to the latin root of the The suffix –ic to the latin root of the metallic ion that has the higher charge.metallic ion that has the higher charge.

Traditional system of Traditional system of namingnaming

Metals that follow traditional method is Metals that follow traditional method is copper (cuprous, cupric)copper (cuprous, cupric)

Iron (ferrous, ferric)Iron (ferrous, ferric) Mercury (mercurous, mercuric)Mercury (mercurous, mercuric) Lead (plumbous plumbic)Lead (plumbous plumbic) Tin (stannous stannic)Tin (stannous stannic)

Stock systemStock system

Name of the metal followed by a roman Name of the metal followed by a roman numeral. The roman numeral tells the numeral. The roman numeral tells the charge on the ion.charge on the ion.

For exampleFor example Copper, iron, mercury, lead, tinCopper, iron, mercury, lead, tin

naming compounds

Documents

sodium ion

silver ion

hydroxide ion

bromide ion

silveri ion

silverii ion

anion naminghydride

h nitride ion