Ionic Bonding and Ionic Ionic Bonding and Ionic CompoundsCompounds

I can classify a bond as ionic and I can classify a bond as ionic and describe the characteristics including describe the characteristics including bond length, bond energy, and lattice bond length, bond energy, and lattice

structure structure

What is the characteristics of an What is the characteristics of an ionic bond and how do they ionic bond and how do they compare to covalent bonds?compare to covalent bonds?

I canI can Define Ionic and covalent bondsDefine Ionic and covalent bonds List the properties that characterize the type List the properties that characterize the type

of bondsof bonds Predict the characteristics and properties of a Predict the characteristics and properties of a

compound based on the type of bond.compound based on the type of bond.

Ionic compoundsIonic compounds

Metal plus nonmetalMetal plus nonmetal Cation plus anionCation plus anion + ion plus – ion+ ion plus – ion Remember that the positive charge must Remember that the positive charge must

cancel the negative chargecancel the negative charge

Formula Units Formula Units

Simplest collection of atom from which an Simplest collection of atom from which an ionic compound’s formula can be ionic compound’s formula can be established.established.

Remember that the overall charge on a Remember that the overall charge on a ionic compound is neutral.ionic compound is neutral.

ExamplesExamples

NaNa++ -- Cl -- Cl- - ----- NaCl ----- NaCl Notice that the charges are cancelled out.Notice that the charges are cancelled out. The name is sodium chlorideThe name is sodium chloride CaCa+2+2 F F------ CaF---- CaF22

Notice that the charges cancel out Notice that the charges cancel out because 2 F and 1 Ca.because 2 F and 1 Ca.

Ca +2 F - F -Ca +2 F - F -

Two ways to create Formula UnitsTwo ways to create Formula Units

1. Add ions until the charges cancel1. Add ions until the charges cancel 2. Criss-Cross method2. Criss-Cross method

CaCa+2+2 F F-- CaCa1 1 FF22

PracticePractice

Li and FLi and F Na and BrNa and Br Ca and ICa and I

Lewis structuresLewis structures

Draw the lewis structure for LiDraw the lewis structure for Li Draw the lewis structure for FDraw the lewis structure for F Show the transfer of electronsShow the transfer of electrons

Ionic CharacteristicsIonic Characteristics

Ionic compounds will often form crystal Ionic compounds will often form crystal lattice structures. lattice structures.

Purple is Sodium NaPurple is Sodium Na

Green is ClGreen is Cl

Ionic CharacteristicsIonic Characteristics

Bond Strength in ionic compounds, amount of Bond Strength in ionic compounds, amount of energy released when separated ions in a gas energy released when separated ions in a gas come together to form a crystalline solid.come together to form a crystalline solid.

Lattice energy is the energy released when one Lattice energy is the energy released when one mole of an ionic crystalline compound is formed mole of an ionic crystalline compound is formed from gaseous ions. from gaseous ions.

Strong bonds, Increased melting/boiling point Strong bonds, Increased melting/boiling point (Do not vaporize as readily as covalent)(Do not vaporize as readily as covalent)

Ionic bonds are strong and have Ionic bonds are strong and have the following propertiesthe following properties

High melting and boiling pointsHigh melting and boiling points HardHard BrittleBrittle In a molten state, or when dissolved in water In a molten state, or when dissolved in water

ionic compounds are electrical conductors, ionic compounds are electrical conductors, because the ions can move freely to carry the because the ions can move freely to carry the electrical charge.electrical charge.

(solid state- no movement- no electrical (solid state- no movement- no electrical conductivity)conductivity)

Dissolved in water – electrical conductors.Dissolved in water – electrical conductors.

Why are ionic compounds hard but Why are ionic compounds hard but brittle?brittle?

In an ionic crystal, even a slight sift of one In an ionic crystal, even a slight sift of one row of ions relative to another causes a row of ions relative to another causes a large build up of repulsive forces. These large build up of repulsive forces. These forces make it difficult for one layer to forces make it difficult for one layer to move relative to another, causing ionic move relative to another, causing ionic compounds to be hard. If one layer is compounds to be hard. If one layer is moved, however the repulsive forces moved, however the repulsive forces make the layer part completely, causing make the layer part completely, causing ionic compounds to be brittle. ionic compounds to be brittle.

Strong but brittleStrong but brittle

Polyatomic IonsPolyatomic Ions

Atoms that are covalently bonded to each Atoms that are covalently bonded to each other to form a group of atoms that has other to form a group of atoms that has both molecular and ionic characteristics.both molecular and ionic characteristics.

The charge on the polyatomic ion results The charge on the polyatomic ion results from an excess of electrons, or shortage.from an excess of electrons, or shortage.

Polyatomic (-) plus a metalPolyatomic (-) plus a metal Polyatomic (NHPolyatomic (NH44

+ + ) plus a nonmetal) plus a nonmetal

METALLIC BONDINGMETALLIC BONDING

How does metallic bonding compare to How does metallic bonding compare to covalent and ionic.covalent and ionic. Characteristics of metallic bondsCharacteristics of metallic bonds Predict properties based on the bond typePredict properties based on the bond type

Metallic bondsMetallic bonds

Chemical bonding that results from the Chemical bonding that results from the attraction between metal atoms and attraction between metal atoms and surrounding sea of electrons surrounding sea of electrons

Sea of electrons is due to the fact that Sea of electrons is due to the fact that there are overlapping empty orbital and there are overlapping empty orbital and the delocalized electrons can move freely the delocalized electrons can move freely throughout the entire metal.throughout the entire metal.

Electrically chargedElectrically charged

Metallic BondingMetallic Bonding

What are the properties of metals?What are the properties of metals?

Why do they have these propertiesWhy do they have these properties

Metallic PropertiesMetallic Properties

High electrical conductorHigh electrical conductor High thermal conductor (free e-)High thermal conductor (free e-) Absorb a wide range of light frequencies because of the Absorb a wide range of light frequencies because of the

small energy differences between orbital's. – makes small energy differences between orbital's. – makes them shinnythem shinny

Malleability – ability of a substance to be hammered into Malleability – ability of a substance to be hammered into a thin sheeta thin sheet

Ductility – ability of a substance to be drawn into a wire.Ductility – ability of a substance to be drawn into a wire. This is possible because the metallic bonding is th same in all This is possible because the metallic bonding is th same in all

directions throughout the solid. One plane can slide past the directions throughout the solid. One plane can slide past the other plane without encountering any; resistance or breaking any other plane without encountering any; resistance or breaking any bonds.bonds.

Metallic Bond Strength Metallic Bond Strength

Metallic bond strength varies with the Metallic bond strength varies with the nuclear charge of the metal atoms and the nuclear charge of the metal atoms and the number of electrons in the metal’s electron number of electrons in the metal’s electron sea. sea.

Reflected in the heat of Vaporization. Reflected in the heat of Vaporization. When a metal is vaporized, the bonded When a metal is vaporized, the bonded atoms in the normal (usually solid) state atoms in the normal (usually solid) state are converted to individual metal atoms in are converted to individual metal atoms in the gaseous state.the gaseous state.

Metallic Bonding Heat of Metallic Bonding Heat of vaporizationvaporization

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