Chapter 8Chapter 8Ionic CompoundsIonic Compounds

Formation of IonsFormation of Ions

►Which type of elements are the most Which type of elements are the most stable (least willing to undergo change)?stable (least willing to undergo change)?

►How many valence electrons do they How many valence electrons do they have?have?

►What would you expect of the other What would you expect of the other elements to increase their stability?elements to increase their stability?

Octet RuleOctet Rule

►Octet Rule- Octet Rule- atoms gain, lose, or atoms gain, lose, or share electrons in order to acquire share electrons in order to acquire a full set of 8 valence electronsa full set of 8 valence electrons..

Ex. sodiumEx. sodium►A A sodium ionsodium ion is more stable than the is more stable than the neutral neutral

sodium atom because it now has 8 sodium atom because it now has 8 valence electrons.valence electrons.

IonsIons

►Cation: Cation: A positively charged ion A positively charged ion formed when an atom loses an formed when an atom loses an electronelectron

►Anion- Anion- A negatively charged ion A negatively charged ion formed when an atom gains an formed when an atom gains an electronelectron

Chemical BondsChemical Bonds

►Chemical bondChemical bond- - an attraction an attraction (force) between atoms that holds (force) between atoms that holds them togetherthem together

3 Types of Bonds3 Types of Bonds

1. 1. Nonpolar covalent bondNonpolar covalent bond- Valence electrons - Valence electrons are shared are shared equallyequally between bonded atoms between bonded atoms

2. 2. Polar covalent bondPolar covalent bond- Valence electrons are - Valence electrons are shared shared unequally unequally between the bonded atoms.between the bonded atoms.

3. 3. Ionic bondIonic bond- Valence electrons are - Valence electrons are transferred transferred from one atom to another, from one atom to another, forming ions. These oppositely charged ions forming ions. These oppositely charged ions attract holding ionic compounds together.attract holding ionic compounds together.

Ionic BondsIonic Bonds

► Ionic compound – Ionic compound – compound made up of positive and compound made up of positive and

negative ions that combine to be negative ions that combine to be neutralneutral

consists of a metal and a nonmetal consists of a metal and a nonmetal OR a metal and a polyatomic ionOR a metal and a polyatomic ion

Formation of Ionic Cmpds.Formation of Ionic Cmpds.

►Formation of ionic compounds-Formation of ionic compounds-compounds form to get 8 valence compounds form to get 8 valence electronselectrons

Using Electron Configurations:Using Electron Configurations:►Ex. Na and Cl to NaEx. Na and Cl to Na++ and Cl and Cl-- = NaCl = NaCl

Using electron-dot notationUsing electron-dot notationEx. Na and ClEx. Na and Cl to Nato Na++ and Cl and Cl-- = NaCl = NaCl

IonsIons

► Formula unit-Formula unit-Simplest ratio of the ions Simplest ratio of the ions represented in an ionic compoundrepresented in an ionic compound

Ex. MgClEx. MgCl22

►Oxidation number (charge)Oxidation number (charge) –Equals the –Equals the number of electrons transferred from or to number of electrons transferred from or to an atom in order to form an ion (the charge an atom in order to form an ion (the charge of a monatomic ion)of a monatomic ion)

Written asWritten as superscriptssuperscripts-number to the upper right of -number to the upper right of symbolsymbol

Positive oxidation number-Positive oxidation number-electrons are transferred electrons are transferred fromfrom

Negative oxidation number-Negative oxidation number-electrons are transferred toelectrons are transferred to

Binary Ionic CompoundsBinary Ionic Compounds

Binary ionic compounds Binary ionic compounds are composed of a metal cation and a are composed of a metal cation and a nonmetal anion.nonmetal anion.

Writing Ionic Chemical Formulas:Writing Ionic Chemical Formulas:1. Cation symbol first; followed by the anion symbol1. Cation symbol first; followed by the anion symbol2. Subscripts (2. Subscripts (numbers to the lower right of a symbol numbers to the lower right of a symbol that that represent the number of ions of each elementrepresent the number of ions of each element) ) are used to are used to get an overall neutral compound.get an overall neutral compound.

Write the chemical formulas for the following compounds:Write the chemical formulas for the following compounds:1. sodium chloride1. sodium chloride 5. manganese (II) nitride5. manganese (II) nitride2. aluminum sulfide2. aluminum sulfide 6. lead (IV) phosphide6. lead (IV) phosphide3. magnesium nitride3. magnesium nitride4. zinc oxide4. zinc oxide

Binary Ionic Cmpds.Binary Ionic Cmpds.

Naming binary ionic compounds:Naming binary ionic compounds:1. Name the cation first and the anion second1. Name the cation first and the anion second

2. Use the element name for the cation2. Use the element name for the cation3. For the anion, take the 3. For the anion, take the root of the root of the

elementelement name plus the name plus the suffix –idesuffix –ide..

Examples:Examples:

1. CaCl1. CaCl22 2. Ba2. Ba33NN22

3. Na3. Na22OO

Using Roman NumeralsUsing Roman Numerals

Ions with multiple charges:Ions with multiple charges:

Transition metals and metals in group 4A of the Transition metals and metals in group 4A of the periodic table often have more than one periodic table often have more than one charge. charge. (Exception zinc, silver, cadmium)(Exception zinc, silver, cadmium)

Examples:Examples:

1. PbO1. PbO22 2. MnN 2. MnN

3. MnCl3. MnCl33 4. FeF 4. FeF33

5. GaI5. GaI22

Polyatomic IonsPolyatomic Ions

► Polyatomic ionsPolyatomic ions-an ion made up of more -an ion made up of more than one elementthan one element

►Oxyanion-Oxyanion-polyatomic ion composed of polyatomic ion composed of an element, usually a nonmetal, an element, usually a nonmetal, bonded to one or more oxygen atomsbonded to one or more oxygen atoms.. Ex.Ex.

-the ion with more oxygen atoms use -the ion with more oxygen atoms use the suffix the suffix –ate–ate

-the ion with less oxygen atoms use -the ion with less oxygen atoms use the suffix the suffix –ite–ite

Polyatomic IonsPolyatomic Ions

Ionic compounds with polyatomic ions:Ionic compounds with polyatomic ions:► Charge applies to entire group of atomsCharge applies to entire group of atoms► Polyatomic ions act as Polyatomic ions act as individual ionsindividual ions so you so you

can write chemical formulas the same way as can write chemical formulas the same way as binary compounds.binary compounds.

Examples:Examples:1. Ammonium chloride1. Ammonium chloride2. Aluminum carbonate2. Aluminum carbonate3. Calcium phosphate3. Calcium phosphate4. Iron(III) perchlorate4. Iron(III) perchlorate

Polyatomic IonsPolyatomic Ions

Naming ionic compounds with polyatomic ionsNaming ionic compounds with polyatomic ions

1. Name the cation first, followed by the anion.1. Name the cation first, followed by the anion.

2. If the compound contains a polyatomic ion, 2. If the compound contains a polyatomic ion, simply name the ion.simply name the ion.

Examples:Examples:

1.1. CaCOCaCO33 2. NH2. NH44ClCl

3. Al(ClO3. Al(ClO33))33 4. CoCO4. CoCO33

1.1. nickel (II) phosphidenickel (II) phosphide

2.2. copper (III) chromatecopper (III) chromate

3.3. potassium sulfitepotassium sulfite

4.4. silver nitratesilver nitrate

5.5. FeFe22(SO(SO44))33

6.6. CaICaI22

7.7. PbOPbO

Properties of Ionic Cmpds.Properties of Ionic Cmpds.

Properties of Ionic Compounds:Properties of Ionic Compounds:

► Crystal latticeCrystal lattice-3-D geometric arrangement -3-D geometric arrangement of particles that is formed because of a of particles that is formed because of a strong attraction of positive ions and strong attraction of positive ions and negative ions in an ionic compound negative ions in an ionic compound

►High melting points and boiling points, and High melting points and boiling points, and high degree of hardness-high degree of hardness-Because the Because the bond is very strong, it takes a lot of bond is very strong, it takes a lot of energy to break apart the bondenergy to break apart the bond

Properties of Ionic Cmpds.Properties of Ionic Cmpds.

► Ionic compounds are Ionic compounds are brittlebrittle

► ElectrolyteElectrolyte-Ionic compounds dissolved in liquids are -Ionic compounds dissolved in liquids are good conductors of electricity because the ions are good conductors of electricity because the ions are free to movefree to move

► Energy changes occur when ionic compounds formEnergy changes occur when ionic compounds form A positive ion to a negative ion is always A positive ion to a negative ion is always

exothermic.exothermic. Lattice energy-Lattice energy-energy needed to separate the energy needed to separate the

ions of the ionic compound. (Strength of ions of the ionic compound. (Strength of holding ions).holding ions).

The more negative the number, the stronger The more negative the number, the stronger the bondthe bond..

Naming Binary AcidsNaming Binary Acids

Acid-Acid-A compound that produces hydrogen A compound that produces hydrogen ions in solution (hydrogen in front)ions in solution (hydrogen in front)..

2 types of acids: 2 types of acids: binary acids binary acids and and oxyacidsoxyacids

Naming binary acids (Hydrogen and one other Naming binary acids (Hydrogen and one other element)element)

1. The prefix 1. The prefix hydro-hydro- is used to name the is used to name the hydrogen part of the compound.hydrogen part of the compound.

2. Add the root of the second element and 2. Add the root of the second element and the the suffix suffix -ic-ic, and finally the word , and finally the word acidacid..

Naming AcidsNaming Acids

Examples:Examples:

1.1. HClHCl 2. HBr2. HBr 3. H3. H33PP

4. H4. H22S S

Formulas for Binary AcidsFormulas for Binary Acids

Examples:Examples:

1.1. Hydrosulfuric acidHydrosulfuric acid

2.2. Hydrofluoric acidHydrofluoric acid

3.3. Hydronitric acidHydronitric acid

OxyacidsOxyacids

Naming oxyacids (Naming oxyacids (An acid that An acid that contains H and an oxyanioncontains H and an oxyanion))

1. Identify anion1. Identify anion

2. Use a form of the 2. Use a form of the anionanion + a + a suffixsuffix + + the the word word acidacid..

3. If the anion ends in:3. If the anion ends in: -ate-ate, replace it with the suffix , replace it with the suffix –ic–ic -ite-ite, replace it with the suffix , replace it with the suffix –ous–ous

OxyacidsOxyacids

Examples:Examples:

1. H1. H22SOSO44 2. H2. H22SOSO33

3. HClO3. HClO33

Examples:Examples:

1. perchloric acid1. perchloric acid 2. nitric acid2. nitric acid

3. Chromic acid3. Chromic acid 4. hydronitric 4. hydronitric acidacid

Metallic BondingMetallic Bonding

Metallic bonding-Metallic bonding-bonding due to attraction between bonding due to attraction between metal atoms and a sea of electrons. metal atoms and a sea of electrons.

Explain these properties with bonding concept.Explain these properties with bonding concept.► MalleabilityMalleability-metals can be hammered in -metals can be hammered in sheetssheets..

► DuctilityDuctility-metals can be drawn into -metals can be drawn into wireswires

► Boiling points- Boiling points- atoms must be separated from the atoms must be separated from the group of cations and electronsgroup of cations and electrons

► Good conductorsGood conductors-movement of mobile electrons around -movement of mobile electrons around positive cationspositive cations

AlloysAlloys

Alloys-Alloys-mixture of elements that has metallic mixture of elements that has metallic propertiesproperties

2 types of alloys2 types of alloys

1. 1. Substitutional AlloySubstitutional Alloy- Atoms of the - Atoms of the original metallic solid original metallic solid replacedreplaced by other by other metal atoms of similar size.metal atoms of similar size.

2. 2. Interstitial AlloyInterstitial Alloy -The small holes in a -The small holes in a metallic crystal are metallic crystal are filledfilled with smaller atoms with smaller atoms