chapter 7 ionic and metallic bonding mr. samaniego lawndale high school

Chapter 7Chapter 7Ionic and Metallic BondingIonic and Metallic Bonding

Mr. SamaniegoMr. Samaniego

Lawndale High SchoolLawndale High School

Section 7.1 - IonsSection 7.1 - Ions

• Valence Electrons – electrons in the highest occupied energy level of an atom

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

•When Mendeleev arranged his periodic table according to properties, he didn’t know that it was also due to the number of bonding electrons

•The reason that certain elements were grouped together was because they have the same number of valence electrons

He 2 e-

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

1.1. KK 6. Be6. Be

2.2. PP 7. Li7. Li

3.3. CC 8. He8. He

4.4. OO 9. Ne9. Ne

5.5. NN 10. B10. B

Electron Dot Structure Electron Dot Structure A diagram that shows valence electrons A diagram that shows valence electrons

as dots around the element symbolas dots around the element symbol

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

Valence ElectronsValence ElectronsThe reason that valence electrons are so The reason that valence electrons are so

important is that they are the only important is that they are the only electrons involved in bondingelectrons involved in bonding

Octet RuleOctet Rule

The Octet Rule states that all atoms The Octet Rule states that all atoms want 8 electrons in their valence want 8 electrons in their valence shellsshells, just like the noble gases , just like the noble gases (except He)(except He)

Remember that all atoms want to be like Remember that all atoms want to be like the noble gases because their s and p the noble gases because their s and p orbitals are completely filled, which orbitals are completely filled, which makes them unreactive and stablemakes them unreactive and stable

Satisfying the Octet RuleSatisfying the Octet Rule

In order for atoms to combine together to In order for atoms to combine together to obtain 8 valence electrons, they transfer obtain 8 valence electrons, they transfer electrons (either gain or lose electrons)electrons (either gain or lose electrons)

In forming compounds, atoms want to In forming compounds, atoms want to achieve a noble gas configurationachieve a noble gas configuration

Some atoms will gain electrons, Some atoms will gain electrons, while other atoms will lose electronswhile other atoms will lose electrons

Filling Order: 1s 2s 2p 3s 3p 4s 3d 4pFilling Order: 1s 2s 2p 3s 3p 4s 3d 4p

Draw the orbital diagram for SodiumDraw the orbital diagram for Sodium

Draw the orbital diagram for MagnesiumDraw the orbital diagram for Magnesium

Draw the orbital diagram for FluorineDraw the orbital diagram for Fluorine

Draw the orbital diagram for OxygenDraw the orbital diagram for Oxygen

Cation versus AnionCation versus AnionRemember that atoms are electrically Remember that atoms are electrically

neutral because they have the same neutral because they have the same number of protons and electronsnumber of protons and electrons

How are electrons transferred?How are electrons transferred?

Metals lose valence electronsMetals lose valence electrons

Nonmetals gain valence electronsNonmetals gain valence electrons

BondingBonding

Once an atom has a stable octet, it is Once an atom has a stable octet, it is happy and does not want to react anymorehappy and does not want to react anymore

Atoms without stable octets are Atoms without stable octets are sad and want to react with other sad and want to react with other atoms to achieve a stable octetatoms to achieve a stable octet

Why don’t noble gases want to form bonds?Why don’t noble gases want to form bonds?

Why do atoms form bonds?Why do atoms form bonds?1. To have a full octet1. To have a full octet2. To be more stable2. To be more stable

3. To be less reactive3. To be less reactive

How do atoms become more How do atoms become more stable and less reactive?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

Charges on the Periodic TableCharges on the Periodic Table

PracticePractice What are the charges on the following elements?What are the charges on the following elements?

1.1. CalciumCalcium

2.2. OxygenOxygen

3.3. ChlorineChlorine

4.4. HydrogenHydrogen

5.5. CesiumCesium

6.6. HeliumHelium

7.7. KryptonKrypton

8.8. AluminumAluminum

Section 7.2 – Ionic BondsSection 7.2 – Ionic Bonds

Ionic Compounds are METAL cations and Ionic Compounds are METAL cations and NONMETAL anions held together by NONMETAL anions held together by electrostatic forceselectrostatic forces

Ionic compounds are formed through Ionic compounds are formed through transferring or exchanging electronstransferring or exchanging electrons

Example…Example…Sodium Chloride (Salt, NaCl) is an Sodium Chloride (Salt, NaCl) is an

example of an ionic compoundexample of an ionic compound

PracticePractice

Which of the following are ionic compounds?Which of the following are ionic compounds?1.1. LiClLiCl

2.2. NaSNaS

3.3. CC22HH44

4.4. MgBrMgBr22

5.5. HH22OO

6.6. SiCSiC

7.7. RbRb33PP

8.8. CsICsI

Ionic ChargesIonic ChargesAlthough they are composed of Although they are composed of

positive and negative charges, positive and negative charges, ionic compounds are overall ionic compounds are overall electrically neutral electrically neutral because their because their charges will cancel outcharges will cancel out

For example…For example…NaNa+1+1 will bond with Cl will bond with Cl-1-1

MgMg2+2+ will bond with O will bond with O2-2-

AlAl3+3+ will bond with N will bond with N3-3-

Two KTwo K+1+1 can also bond with One S can also bond with One S2-2-

Writing Chemical FormulasWriting Chemical Formulas

AlAl3+3+ SS2-2-

AlAl22SS33

AlAl3+3+ SS2-2-SS2-2-

The numbers on top are the charges, The numbers on top are the charges, while the numbers on the bottom tell while the numbers on the bottom tell

how many atoms there arehow many atoms there are

PracticePractice

Write as many compounds as you can Write as many compounds as you can with the following ions. Remember with the following ions. Remember

that the overall charge must be zero. that the overall charge must be zero. There are 9 possible.There are 9 possible.

Li+1 Ca2+ Al3+ N3- S2- Cl-1

SaltSalt

Salt crystals are repeating patterns of Salt crystals are repeating patterns of positive and negative ions held together by positive and negative ions held together by electrostatic attractionelectrostatic attraction

Ionic BondingIonic Bonding

When cations and anions transfer When cations and anions transfer electrons, a SALT is formedelectrons, a SALT is formed

Draw the electron dot structure for the Draw the electron dot structure for the following atomsfollowing atomsLi and BrLi and BrMg and OMg and OTwo K and One STwo K and One SOne Sr and Two FOne Sr and Two F

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 diagrams

1.1. NaFNaF

2.2. MgOMgO

3.3. LiLi22SS

4.4. CaClCaCl22

5.5. AlNAlN

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

Metal atoms are Metal atoms are arranged in very arranged in very compact and compact and orderly patternsorderly patterns

Metallic BondMetallic BondA Metallic Bond is a bond between metal A Metallic Bond is a bond between metal

cations surrounded by a sea of electronscations surrounded by a sea of electrons

Metallic BondMetallic Bond

The The attraction of attraction of the free the free floating floating valence valence electrons electrons holds them holds them togethertogether

Crystalline Structure of MetalsCrystalline Structure of Metals(Page 202)(Page 202)

Properties of MetalsProperties of Metals

1.1.Good Conductors of Good Conductors of electrical currentelectrical current

2. Ductile (ability 2. Ductile (ability to be stretched)to be stretched)

3. Malleable 3. Malleable (ability to be (ability to be shaped)shaped)

AlloysAlloys

Alloys are a mixture of two or more Alloys are a mixture of two or more elements, at least one being a metalelements, at least one being a metal

Very few of the metal objects you use Very few of the metal objects you use everyday are pure metalseveryday are pure metals

Alloys are important because the Alloys are important because the combination of metals are stronger combination of metals are stronger than the single metal by itselfthan the single metal by itself

Examples of Alloy CombinationsExamples of Alloy CombinationsBrass – copper and zincBrass – copper and zincSterling Silver – silver and copperSterling Silver – silver and copperBronze – copper and tinBronze – copper and tinSteel – iron, carbon, boron, chromium, Steel – iron, carbon, boron, chromium,

manganese, molybdenum, nickel, manganese, molybdenum, nickel, tungsten, vanadiumtungsten, vanadium

Stainless Steel – iron, chromium, carbon, Stainless Steel – iron, chromium, carbon, nickelnickel

Cast Iron – iron and carbonCast Iron – iron and carbon

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