Chapter 8 Ionic Bonding

Question of the Day  Question: Write the electron level configurations for the Noble gases. He Ar ArKr Xe Xe

I. Chemical Bonds  A. The force that holds two atoms together. 1. Why do atoms form bonds? 1. Why do atoms form bonds? a. to acquire 8 electrons in the a. to acquire 8 electrons in the valence shell (like noble gases 2. How do atoms form bonds? valence shell (like noble gases 2. How do atoms form bonds? a. atoms may lose, gain or share a. atoms may lose, gain or share electrons to get 8 in the valence electrons to get 8 in the valence shell shell

A. Chemical Bond and valence electron 1.The electrons responsible for the chemical properties of atoms are those in the outer energy level: VALENCE ELECTRONS. a.Valence electrons - The electrons in the outer energy level. b.Inner electrons -those in the energy levels below.

Keeping Track of Electrons 2. Atoms in the same column a. Have the same outer electron configuration. b. Have the same valence electrons. c. Easily found by looking up the group number on the periodic table. d. Group 2A - Be, Mg, Ca, etc.- 2 valence electrons

B. Electron Dot Diagrams: Lewis Structures 1. A way of keeping track of valence electrons. 2. How to write them 3. Write the symbol. 4. Put one dot for each valence electron 5. Don’t pair up until they have to X

The Electron Dot diagram for Nitrogen l Nitrogen has 5 valence electrons. l First we write the symbol. N l Then add 1 electron at a time to each side. l Until they are forced to pair up.

Write the electron dot diagram for  Na  Mg CCCC OOOO FFFF  Ne  He

C. Ion Formation in Representative Elements Group Gain or Lose Charge of Ion 1 (1A) lose (2A) lose (3A) lose (4A) lose or gain 4* +4,-4* 15 (5A) gain (6A) gain (7A) gain 1 -1

C. Electron Configurations for Cations 1. Metals lose electrons to attain noble gas configuration. 2. They make positive ions. 3. If we look at electron configuration it makes sense.  Na 1s 2 2s 2 2p 6 3s 1 : 1 valence electron  Na + 1s 2 2s 2 2p 6 : noble gas configuration

Electron Dots For Cations  Metals will have few valence electrons Ca

Electron Dots For Cations  Metals will have few valence electrons  These will come off Ca

Electron Dots For Cations  Metals will have few valence electrons  These will come off  Forming positive ions Ca +2

Write the electron configuration diagram label as anion or cation  Na  Mg PPPP OOOO FFFF  Cl KKKK

D. Electron Configurations for Anions 1. Nonmetals gain electrons to attain noble gas configuration. 2. They make negative ions. 3. If we look at electron configuration it makes sense.  S 1s 2 2s 2 2p 6 3s 2 3p 4 : 6 valence electrons  S -2 1s 2 2s 2 2p 6 3s 2 3p 6 : noble gas configuration.

Electron Dots For Anions  Nonmetals will have many valence.electrons.  They will gain electrons to fill outer shell. P P -3

E. Stable Electron Configuration 1.All atoms react to achieve noble gas configuration. 2.Noble gases have 2 s and 6 p electrons valence electrons. 4. Also called the octet rule. Ar

I. Properties of Ionic Compounds View Ionic video a. Crystalline structure. b. A regular repeating arrangement of ions in the solid. c. Structure is rigid.

II. Ionic Bonding A. Anions and cations are held together by opposite charges. B. Ionic compounds are called salts. C. Simplest ratio is called the formula unit. D.The bond is formed through the transfer of electrons. E. Electrons are transferred to achieve noble gas configuration.

II.Formation and Nature of Ionic Bonds F. 1. atom “M” loses electron(s)  cation 2. atom “N” gains electron(s)  anion 2. atom “N” gains electron(s)  anion 3. cation and anion attract each other 3. cation and anion attract each other a. electrostatic attraction a. electrostatic attraction 4. the electrostatic force that holds the 4. the electrostatic force that holds the oppositely charged ions together is oppositely charged ions together is the ionic bond the ionic bond

Sodium loses an electron forming a (+) ion. Chlorine gains an electron forming a ( - ) ion. Electrostatic attraction between the (-) and (+) ion forms the ionic bond between sodium and chlorine Electrostatic attraction between the (-) and (+) ion forms the ionic bond between sodium and chlorine

B. Ionic Compounds 1. compounds containing ionic bonds 1. compounds containing ionic bonds 2. types of ionic compounds 2. types of ionic compounds a. oxides – metal + oxygen a. oxides – metal + oxygen Na 2 O, CaO, Al 2 O 3, Fe 2 O 3 Na 2 O, CaO, Al 2 O 3, Fe 2 O 3 b. salt – metal + nonmetal b. salt – metal + nonmetal NaCl CaF AgCl KI NaCl CaF AgCl KI c. binary compounds – two elements c. binary compounds – two elements 1)all of the compounds in a and b 1)all of the compounds in a and b are binary compounds are binary compounds

 D. monoatomic ion - one atom 1) ex. K + Fe 3+ O 2- N 3- 1) ex. K + Fe 3+ O 2- N 3- E. polyatomic ion – ion with more than E. polyatomic ion – ion with more than one atom that acts as a single ion one atom that acts as a single ion NO 3 - OH - SO 4 2- NH 4 + NO 3 - OH - SO 4 2- NH 4 +

 Work on ion formation and the periodic table worksheet.  Complete notes sheet

III. Names and Formulas A.Formulas for Ionic Compounds 1. vocabulary 1. vocabulary a. formula unit – simplest ratio of a. formula unit – simplest ratio of ions in a compound ions in a compound 1) ex. NaCl MgBr 2 AlCl 3 1) ex. NaCl MgBr 2 AlCl 3 b. monoatomic ion - one atom b. monoatomic ion - one atom 1) ex. K + Fe 3+ O 2- N 3- 1) ex. K + Fe 3+ O 2- N 3- c. oxidation number – charge of c. oxidation number – charge of the monoatomic ion the monoatomic ion 1) ex. K is +1 O is -2 N is -3 1) ex. K is +1 O is -2 N is -3

d. polyatomic ion – ion with more than d. polyatomic ion – ion with more than one atom that acts as a single ion one atom that acts as a single ion NO 3 - OH - SO 4 2- NH 4 + NO 3 - OH - SO 4 2- NH composition of ionic compounds 2. composition of ionic compounds a. metal + nonmetal (NaCl) a. metal + nonmetal (NaCl) b. metal + polyatomic ion(MgSO 4 ) b. metal + polyatomic ion(MgSO 4 ) c. polyatomic ion + nonmetal (NH 4 Cl) c. polyatomic ion + nonmetal (NH 4 Cl) d. polyatomic ion + polyatomic ion d. polyatomic ion + polyatomic ion NH 4 NO 3 NH 4 NO 3

B. Formulas For Ionic Compounds 1. write formula for the cation first, then 1. write formula for the cation first, then the anion the anion 2. use subscripts to indicate number of 2. use subscripts to indicate number of ions (criss-cross the charges) ions (criss-cross the charges) a. sum of charges should equal 0 a. sum of charges should equal 0 b. never change subscripts in b. never change subscripts in polyatomic ions polyatomic ions c. put polyatomic ions in parentheses c. put polyatomic ions in parentheses when there is more than one when there is more than one

Sodium Chloride Crystal

Ionic Bonding NaCl

Ionic Bonding: Lewis Structure Na + Cl -

Ionic Bonding  All the electrons must be accounted for! CaP

Ionic Bonding CaP

Ionic Bonding Ca +2 P

Ionic Bonding Ca +2 P Ca

Ionic Bonding Ca +2 P -3 Ca

Ionic Bonding Ca +2 P -3 Ca P

Ionic Bonding Ca +2 P -3 Ca +2 P

Ionic Bonding Ca +2 P -3 Ca +2 P Ca

Ionic Bonding Ca +2 P -3 Ca +2 P Ca

Ionic Bonding Ca +2 P -3 Ca +2 P -3 Ca +2

Ionic Bonding Ca 3 P 2 Formula Unit

Shortcut  Ca +2 P -3  Ca 3 P 2  Crisscross the charges to become the subscript!!!!!!!!!!!!!!!!!!!!!!!!!

 quiz

I. Properties of Ionic Compounds a. Crystalline structure. b. A regular repeating arrangement of ions in the solid. c. Structure is rigid.

Crystalline structure

Ionic Compounds Ionic compounds consist of a lattice a lattice of positive of positive and negative ions. Lattice: three dimensional array of ions NaCl:

Crystalline Structure  1. forms a lattice crystal- a 3-d geometric structure. a. each negative ion is surrounded by positive ions. b. Lattice energy- the energy required to break one mole of ions from the ionic bond the more energy – the harder it is to break-pg 220

Ionic properties d. Ions are strongly bonded- because of strong forces between ions they have 1. High melting points 2. high boiling point 2. high boiling point 3. high hardness scale 4. very rigid 5. very brittle

Ionic solids are brittle

 Strong Repulsion breaks crystal apart.

Activity  Demo- Burn to Create Mg+O=MgO  Check the conductivity of:  1. NaCl- solid  2. NaCl-aqueous solution  3. Distilled water  4. Tap  5. MgO-solid  6. MgO-aqueous solution  7. use magnifying glass to view NaCl

E. Conductivity E. Conductivity 1.Conducting electricity is allowing charges to move. 2.In a solid, the ions are locked in place. 3. Ionic solids are insulators. 4. When melted, the ions can move around. 5. Melted ionic compounds conduct. 6. First get them to 800ºC. 7. ELECTROLYTE-Dissolved in water they conduct. (aqueous solution)

Building Ionic Compounds Binary compound - metallic cation bonded to nonmetallic anion 1. Oxide- When a metal is ionically bonded to Oxygen Salt - Metal + Non-metal

ACTIVITY:   MAKE TAB CUTOUTS OF THE VALENCE SHELL OF   AL, O, Na, Cl, Mg, Ca   Bond Al O   Mg O   Na Cl  Build just one formula unit- remember it doesn’t exist as one i  Build just one formula unit- remember it doesn’t exist as one in nature – it is a crystal of many formula units where each – is surrounded by a +

Polyatomic Ions  An ion made up of two or more atoms bonded together that acts as a single unit with a net charge. Build with tabs NH 4, OH, Write the polyatomic ion and the charge it has. Na(OH)- a balance compound Mg +2 (OH ) –1 Mg(0H) 2 a balanced compound Mg(0H) 2 a balanced compound

Naming Compounds.A. Formulas For Ionic Compounds 1. write formula for the cation first, then 1. write formula for the cation first, then the anion the anion 2. use subscripts to indicate number of 2. use subscripts to indicate number of ions (criss-cross the charges) ions (criss-cross the charges) a. sum of charges should equal 0 a. sum of charges should equal 0 b. never change subscripts in b. never change subscripts in polyatomic ions polyatomic ions c. put polyatomic ions in parentheses c. put polyatomic ions in parentheses when there is more than one when there is more than one

A.Writing Names of Ionic Compounds 1. write name of cation first then anion 1. write name of cation first then anion a. this is the same order in which a. this is the same order in which elements appear in the formula elements appear in the formula 2. use Roman numerals to indicate the 2. use Roman numerals to indicate the valence of the cation if it is multivalent valence of the cation if it is multivalent a. examples a. examples CuCl - copper I chloride CuCl - copper I chloride CuCl 2 - copper II chloride CuCl 2 - copper II chloride

3. Name a cation with a polyatomic anion 3. Name a cation with a polyatomic anion A.Name the cation element 1 st B. Name the anion polyatomic ion 2nd B. Name the anion polyatomic ion 2nd ie: NaOH Sodium hydroxide

Naming ionic compounds I. Oxyanion- is a polyatomic ( 2 or more ions bonded) ion where a non-metal bonds with oxygen. A. use the root of the non-metal with the following suffix A. use the root of the non-metal with the following suffix 1. MORE OXYGENS - ATE 2. LESS OXYGENS - ITE IE; NO 2 - Nitrite NO 3 - Nitrate

Naming the halogen group as an oxyanion Naming the halogen group as an oxyanion A. use the root of the halogen with the following suffix and prefix 1. Most oxygens ( usually 4 ) a. prefix - per b. suffix - ate ie: IO 4 - periodate 2. one less oxygen a. suffix - ate io ie: IO 3 - iodate

Halogen as oxyanions 3. two less Oxygen- a. suffix - ite ie: IO2 - iodite 4. 3 less oxygens- a. prefix - hypo b. suffix- ite ie: IO- hypoiodite

I. Metallic Bonds  How atoms are held together in the solid form.  Metals hold onto their valence electrons very weakly.  Think of them as positive ions floating in a sea of electrons.

 LHY LHY LHY

Sea of Electrons  Electrons are free to move through the solid.  Metals conduct electricity.

Metals are Malleable  Hammered into shape (bend).  Ductile - drawn into wires.

Malleable

Malleable  Electrons allow atoms to slide by.

Video  47s 47s 47s

ALLOYS  Alloys are solid solutions made by dissolving metals in other metals. They are prepared by melting the metals together and cooling the mixture.  The properties of alloys differ from those of their component metals. For example stainless steel, an alloy of iron, carbon, chromium and nickel is stronger than iron and more resistant to corrosion.

Name of Alloy Composition ________________________________________ Sterling silver silver, copper Brass copper, zinc, tin Cast iron iron, carbon Steel iron, carbon Stainless steel iron, chromium, carbon, nickle 18 Carat gold gold, silver, copper Pewter tin, copper, bismuth, antimony Plumber’s solder lead, tin

ALLOY  A combination of 2 metals

IV.Metallic Bonds – Properties of Metals A.Metallic Bonds 1. valence electrons are delocalized 1. valence electrons are delocalized a. free to move from atom to atom a. free to move from atom to atom 2. bond is formed by the attraction of 2. bond is formed by the attraction of metal cations for the moving electrons metal cations for the moving electrons 3. “electron sea model” –atoms of 3. “electron sea model” –atoms of metals contribute a “sea” of free metals contribute a “sea” of free moving electrons that move from one moving electrons that move from one atom to another atom to another

Electron Sea Model for Metallic Bonds

Positive Ions Surrounded by Delocalized Electrons

B.Properties of Metals 1. moderately high melting points 1. moderately high melting points 2. high boiling points 2. high boiling points 3. malleable 3. malleable a. can be hammered into sheets a. can be hammered into sheets 4. ductile 4. ductile a. can be drawn into wire a. can be drawn into wire 5. good conductors of heat and electricity 5. good conductors of heat and electricity 6. luster (good reflectors of light) 6. luster (good reflectors of light) 7. hardness and strength varies 7. hardness and strength varies a. greater in transition elements a. greater in transition elements

C. Alloys 1. mixture of two or more elements with 1. mixture of two or more elements with metallic properties metallic properties 2. types 2. types a. substitutional – atoms of similar a. substitutional – atoms of similar size (sterling silver, brass, pewter) size (sterling silver, brass, pewter) b. interstitial – small holes in the b. interstitial – small holes in the crystal filled with smaller atoms crystal filled with smaller atoms (carbon steel) (carbon steel)

The red, blue and yellow circles represent three different metals in an alloy. The blue lines are the delocalized electrons in the metals.

Substitutional Alloy Interstitial Alloy Substitutional Alloy Interstitial Alloy

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