Chapter 7Chapter 7Ionic and Metallic BondingIonic and Metallic Bonding

Ms. WangMs. WangLawndale High SchoolLawndale High School

Section 7.1 - IonsSection 7.1 - Ions

• Valence Electrons – electrons in the highest occupied energy level of an element’s atoms

• To find the valence electrons in an atom of the representative element, simply look at the group number

Electron Configuration and Electron Configuration and Valence ElectronsValence Electrons

Example: How many electrons are in the Example: How many electrons are in the valence shell of sodium?valence shell of sodium?

Step 1: Write the electron configuration of Step 1: Write the electron configuration of sodiumsodium

Na = [Ne]3sNa = [Ne]3s11

Step 2: Count the number of electrons in the Step 2: Count the number of electrons in the valence shell (outermost shell). valence shell (outermost shell).

Determine the Valence electrons Determine the Valence electrons in each of these elementsin each of these elements

1.1. KK 6. Be6. Be2.2. PP 7. Li7. Li3.3. CC 8. He8. He4.4. OO 9. Ne9. Ne5.5. NN 10. B10. B

Electron Dot Structure Electron Dot Structure Diagrams that show valence Diagrams that show valence

electrons as dots electrons as dots

X3 5

1

8

2

6

4 7

PRACTICEPRACTICE

1. K1. K 6. Be6. Be

2. P2. P 7. Li7. Li

3. C3. C 8. He8. He

4. O4. O 9. Ne9. Ne

5. N5. N 10. B10. B

Octet RuleOctet Rule Eight electrons in the highest Eight electrons in the highest

occupied energy level just like the occupied energy level just like the noble gases (except He)noble gases (except He)

Metal elements lose their valence Metal elements lose their valence electronselectrons

Nonmetal elements gain electronsNonmetal elements gain electrons

Formation of CationsFormation of Cations

3s

2p

2s

1s

Sodium atom

Na

Sodium ion

Na+

Neon atom

Ne

Na Na+ + e-

Formation of AnionsFormation of Anions2p

2s

1s

Fluorine atom

F

Fluorine ion

F-

Neon atom

Ne

F + e- F-

PracticePractice

1.1. Show how a Lithium atom becomes an cationShow how a Lithium atom becomes an cation

2. Show how a Calcium atom becomes a cation2. Show how a Calcium atom becomes a cation

3. Show how a Chlorine atom becomes an anion3. Show how a Chlorine atom becomes an anion

4. Show how an Oxygen atom becomes an anion4. Show how an Oxygen atom becomes an anion

BondingBondingOnce an atom has a stable octet, it is Once an atom has a stable octet, it is

happy and doesn’t want to react anymorehappy and doesn’t want to react anymore

Atoms without stable octets, Atoms without stable octets, are sad and want to react with are sad and want to react with another element to achieve a another element to achieve a stable octetstable octet Gain or Lose Valence Gain or Lose Valence ElectronsElectronsComplete this sentence: Complete this sentence:

Noble Gases do not easily form bonds Noble Gases do not easily form bonds because….because….

Why do atoms form bonds?Why do atoms form bonds?To be more chemically stable and less reactiveTo be more chemically stable and less reactive

How do atoms become more How do atoms become more chemically stable and less reactive?chemically stable and less reactive? By having completely filled s and p By having completely filled s and p orbitals just like the noble gases orbitals just like the noble gases

Section 7.2 – Ionic BondsSection 7.2 – Ionic BondsIonic Compounds – metal cations Ionic Compounds – metal cations

and nonmetal anions that are held and nonmetal anions that are held together by electrostatic forcestogether by electrostatic forces

Although ionic compounds are Although ionic compounds are composed of ions, they are composed of ions, they are electrically neutralelectrically neutral

Ionic BondingIonic Bonding An ion is an atom that has gained or lost An ion is an atom that has gained or lost

one or more electrons and thus have an one or more electrons and thus have an electrical charge. electrical charge.

To find the charge of the ion subtract the To find the charge of the ion subtract the number of electrons from the number of number of electrons from the number of protons.protons.

Example: [S]=1sExample: [S]=1s222s2s222p2p663s3s223p3p44 (16 p+, 16e-) (16 p+, 16e-)

[S[S2-2-] 1s] 1s222s2s222p2p663s3s223p3p6 6 (16p+, 18e-)(16p+, 18e-)16 -18 = -216 -18 = -2

Labeling the Periodic TableLabeling the Periodic TableThese elements have the following charges:These elements have the following charges:Group 1A = 1+Group 1A = 1+Group 2A = 2+ Group 2A = 2+ Group 3A = 3+Group 3A = 3+Group 4A = 4+ or 4-Group 4A = 4+ or 4-Group 5A = 3-Group 5A = 3-Group 6A = 2-Group 6A = 2-Group 7A = 1-Group 7A = 1-

When cations and anions form bonds When cations and anions form bonds with each other they are called with each other they are called SALTSSALTS

The + and - charges that cations and anions The + and - charges that cations and anions have causes an attraction between the two have causes an attraction between the two

They come together to form an ionic bond also They come together to form an ionic bond also known as a salt.known as a salt.

Example:Example: NaNa++ ClCl--

NaCl NaCl

SALTS

When cations and anions form bonds When cations and anions form bonds with each other they are called SALTSwith each other they are called SALTS

Example:Example:

Li Li 1s1s 2p2p

FF1s1s 2p2p

Li+

F-LiF

SALTS

Practice Practice Show how the following compounds bond Show how the following compounds bond

with the use of orbital diagramswith the use of orbital diagrams1.1. NaFNaF2.2. KBrKBr3.3. MgOMgO4.4. LiLi22SS

5.5. CaClCaCl226.6. AlNAlN

Ionic BondsIonic Bonds Ionic bond is typically a bond Ionic bond is typically a bond

between a METAL CATION and a between a METAL CATION and a NONMETAL ANIONNONMETAL ANIONThe electrostatic forces between the two The electrostatic forces between the two

types of ions hold them togethertypes of ions hold them together

• Bonds form when metals donate Bonds form when metals donate electrons to nonmetalselectrons to nonmetals

Properties of Ionic CompoundsProperties of Ionic CompoundsCrystallineCrystalline Solid at Room TemperatureSolid at Room TemperatureHigh Melting PointsHigh Melting PointsCan conduct an electric current when Can conduct an electric current when

melted or dissolved in watermelted or dissolved in water

Section 7.3 – Bonding in MetalsSection 7.3 – Bonding in Metals

Metallic bond is a bond between Metallic bond is a bond between metal cations.metal cations.

The attraction of the free floating The attraction of the free floating valence electrons for the positively valence electrons for the positively charged metal ions hold them charged metal ions hold them together. together.

Crystalline Structure of MetalsCrystalline Structure of MetalsMetal atoms are arranged in very compact Metal atoms are arranged in very compact

and orderly patternsand orderly patternsPhysical Properties of MetalsPhysical Properties of Metals

Good Conductors of electrical currentGood Conductors of electrical currentDuctile - can be drawn into wiresDuctile - can be drawn into wiresMalleable – can be hammered or shapedMalleable – can be hammered or shaped

Alloys – mixtures composed of two or Alloys – mixtures composed of two or more elements, at least one being a metalmore elements, at least one being a metal

HomeworkHomework

Chapter 7 AssessmentChapter 7 Assessment#’s 30-44, 48, 53, 55, 56, 58, 59, 60, 62, 63, #’s 30-44, 48, 53, 55, 56, 58, 59, 60, 62, 63,

64, 65, 72, 73, 87, 88, 90, 92, 93, 94, 9564, 65, 72, 73, 87, 88, 90, 92, 93, 94, 95