IONS AND IONIC COMPOUNDSIONS AND IONIC COMPOUNDS

•MONATOMIC IONSMONATOMIC IONS are atoms with a are atoms with a

positive or negative charge. positive or negative charge.

• Taking awayTaking away an electron from an atom gives a an electron from an atom gives a

CATIONCATION with a with a positive chargepositive charge

• AddingAdding an electron to an atom gives an an electron to an atom gives an ANIONANION

with a with a negative chargenegative charge..

PREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGES

In generalIn general

• metalsmetals (Mg) (Mg) lose electrons lose electrons ---> ---> cationscations

– Charge = group numberCharge = group number

• nonmetalsnonmetals (F) (F) gain electronsgain electrons ---> ---> anionsanions

– Charge = group number -8Charge = group number -8

Charges on Charges on Common IonsCommon IonsCharges on Charges on

Common IonsCommon Ions

+3

-4 -1-2-3+1

+2

By losing or gaining e-, atom has same By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.number of e-’s as nearest Group 8A atom.

METALSMETALSM ---> n e- + MM ---> n e- + Mn+n+

where n = periodic groupwhere n = periodic groupNaNa++ sodium ionsodium ionMgMg2+2+ magnesium ionmagnesium ionAlAl3+3+ aluminum ionaluminum ion

Transition metalsTransition metals -->M -->M2+2+or Mor M3+ 3+ are commonare common

FeFe2+2+ iron(II) ioniron(II) ionFeFe3+3+ iron(III) ioniron(III) ionSee Table 9.2 page 255See Table 9.2 page 255

Transition Elements

• Charges of 2+ and 3+ are common

• Roman numeral indicates the charge of the ion

• Classical Name – suffixes indicate charge (sort of)

– ous means less– ic means more

• See Table 9.2 page 255

NONMETALSNONMETALSNONMETALSNONMETALSNONMETAL + n e- ------> XNONMETAL + n e- ------> Xn-n-

where n = 8 - Group no.where n = 8 - Group no.

CC4-4-,carbide,carbide NN3-3-, nitride, nitride OO2-2-, oxide, oxide

SS2-2-, sulfide, sulfide

FF--, fluoride, fluoride

ClCl--, chloride, chloride

Group 7AGroup 6AGroup 4A Group 5A

BrBr--, bromide, bromide

II--, iodide, iodide

Predicting Charges on Monatomic IonsPredicting Charges on Monatomic Ions

POLYATOMIC POLYATOMIC IONSIONS

POLYATOMIC POLYATOMIC IONSIONS

• Groups of atoms with a charge.Groups of atoms with a charge.

• Names end in –ite or –ateNames end in –ite or –ate

– ite means lessite means less

– ate means moreate means more

MEMORIZEMEMORIZE the names and formulas in Table 9.3 page 257. the names and formulas in Table 9.3 page 257.

Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions

HNOHNO33

nitric acidnitric acid

NONO33--

nitrate ionnitrate ion

Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions

NHNH44++

ammonium ionammonium ionOne of the few One of the few

common common polyatomic polyatomic cationscations

Polyatomic Polyatomic IonsIonsPolyatomic Polyatomic IonsIonsCOCO33

2-2-

carbonate ioncarbonate ion

HCOHCO33--

bicarbonate ionbicarbonate ionhydrogen carbonatehydrogen carbonate

POPO443-3-

phosphate ionphosphate ion

CHCH33COCO22--

acetate ionacetate ion

Polyatomic Polyatomic IonsIons

Polyatomic Polyatomic IonsIons

SOSO442-2-

sulfate ionsulfate ion

SOSO332-2-

sulfite ionsulfite ion

Polyatomic Polyatomic IonsIons

Polyatomic Polyatomic IonsIons

Naming Binary Ionic Compounds

• Binary compounds are composed of two elements, a metal and a non-metal.

• Place the name of the cation first and then the name of the anion.– Remember the –ide suffix.

chlorideSodiumThe cation The anion

Writing formulas for Binary Ionic Compounds

• Write the symbol of the cation and the anion (include the charge)

• Add whatever subscripts are needed to balance the charge

• Use the criss-cross method– The charge of one ion becomes the subscript of

the other. Don’t forget to reduce to the empirical formula.

Naming Ternary Ionic Compounds

• Ternary compounds are composed of three or more elements.

• Place the name of the cation first and then the name of the anion.

• Often end in –ite and -ate

StrontiumThe cation

sulfateThe polyatomic ion. Don’t change the name

Writing formulas for Ternary Ionic Compounds• Write the symbol of the cation and the

anion (include the charge)• Add whatever subscripts are needed to

balance the charge• Use parentheses when the compound

contains more than one polyatomic ion• Use the criss-cross method

Naming Binary Molecular Compounds

• Binary compounds are composed of two elements, two non-metals.

• The name identifies the elements and how many of each atom there is in the compound.

• Name the elements in the order they appear in the formula.• Use prefixes to indicate the number of each kind of atom.• Omit mono- when the name has only one atom of the first

element.• Use the suffix –ide for the name of the second element.

9.3

Naming Binary Molecular Compounds

Name these compounds!

• PBr3

• CrBr3

• N2O

• Na2O

• Cl4

• PbI4

• P2O3

• Fe2O3

Writing formulas for Binary Molecular Compounds

• Use the prefixes in the name to determine the subscript of each element in the formula.

Phosphorus pentafluoride

Naming Acids

• Ionic compounds with unique properties

• Contain one or more hydrogen atoms and produce H+ ions when dissolved in water

1. When the name of the anion ends in –ide , the acid name begins with hydro-. The stem of the anion has the suffix –ic and is followed by the word acid.

HCl hydrogen chloride

acid name – hydrochloric acid

2. When the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid.

H2SO3 hydrogen sulfite

Acid name – sulfurous acid

3. When the anion name ends in –ate, the acid name is the stem of the anion with suffix –ic followed by the word acid.

HNO3 hydrogen nitrate

Acid name – nitric acid

Naming Bases

• Ionic compounds with unique properties

• Produce OH- ions when dissolved in water

• Named the same as other ionic compounds – Name of the cation followed by the anion.