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Chapter 7 Ionic and Metallic Bonding Mr. Samaniego Lawndale High School.

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Presentation on theme: "Chapter 7 Ionic and Metallic Bonding Mr. Samaniego Lawndale High School."— Presentation transcript:

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2 Chapter 7 Ionic and Metallic Bonding Mr. Samaniego Lawndale High School

3 Section 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

4 He 2 e -

5 Determine the Valence electrons in each of these elements 1. K6. Be 2. P7. Li 3. C8. He 4. O9. Ne 5. N10. B

6 Electron Dot Structure A diagram that shows valence electrons as dots around the element symbol A diagram that shows valence electrons as dots around the element symbol PRACTICE PRACTICE 1. K6. Be 2. P7. Li 3. C8. He 4. O9. Ne 5. N10. B

7 Valence Electrons The reason that valence electrons are so important is that they are the only electrons involved in bonding The reason that valence electrons are so important is that they are the only electrons involved in bonding

8 Octet Rule The Octet Rule states that all atoms want 8 electrons in their valence shells, just like the noble gases (except He) The Octet Rule states that all atoms want 8 electrons in their valence shells, just like the noble gases (except He) Remember that all atoms want to be like the noble gases because their s and p orbitals are completely filled, which makes them unreactive and stable Remember that all atoms want to be like the noble gases because their s and p orbitals are completely filled, which makes them unreactive and stable

9 Satisfying the Octet Rule In order for atoms to combine together to obtain 8 valence electrons, they transfer electrons (either gain or lose electrons) In order for atoms to combine together to obtain 8 valence electrons, they transfer electrons (either gain or lose electrons) In forming compounds, atoms want to achieve a noble gas configuration In forming compounds, atoms want to achieve a noble gas configuration

10 Some atoms will gain electrons, while other atoms will lose electrons Filling Order: 1s 2s 2p 3s 3p 4s 3d 4p Draw the orbital diagram for Sodium Draw the orbital diagram for Sodium Draw the orbital diagram for Magnesium Draw the orbital diagram for Magnesium Draw the orbital diagram for Fluorine Draw the orbital diagram for Fluorine Draw the orbital diagram for Oxygen Draw the orbital diagram for Oxygen

11 Cation versus Anion Remember that atoms are electrically neutral because they have the same number of protons and electrons Remember that atoms are electrically neutral because they have the same number of protons and electrons

12 How are electrons transferred? Metals lose valence electrons Metals lose valence electrons Nonmetals gain valence electrons Nonmetals gain valence electrons

13 Bonding Once an atom has a stable octet, it is happy and does not want to react anymore Once an atom has a stable octet, it is happy and does not want to react anymore Atoms without stable octets are sad and want to react with other atoms to achieve a stable octet Atoms without stable octets are sad and want to react with other atoms to achieve a stable octet Why don’t noble gases want to form bonds? Why don’t noble gases want to form bonds?

14 Why do atoms form bonds? 1. To have a full octet 2. To be more stable 3. To be less reactive How do atoms become more stable and less reactive? By having completely filled s and p orbitals just like the noble gases

15 Charges on the Periodic Table

16 Practice What are the charges on the following elements? What are the charges on the following elements? 1. Calcium 2. Oxygen 3. Chlorine 4. Hydrogen 5. Cesium 6. Helium 7. Krypton 8. Aluminum

17 Section 7.2 – Ionic Bonds Ionic Compounds are METAL cations and NONMETAL anions held together by electrostatic forces Ionic Compounds are METAL cations and NONMETAL anions held together by electrostatic forces Ionic compounds are formed through transferring or exchanging electrons Ionic compounds are formed through transferring or exchanging electrons

18 Example… Sodium Chloride (Salt, NaCl) is an example of an ionic compound Sodium Chloride (Salt, NaCl) is an example of an ionic compound

19 Practice Which of the following are ionic compounds? Which of the following are ionic compounds? 1. LiCl 2. NaS 3. C 2 H 4 4. MgBr 2 5. H 2 O 6. SiC 7. Rb 3 P 8. CsI

20 Ionic Charges Although they are composed of positive and negative charges, ionic compounds are overall electrically neutral because their charges will cancel out Although they are composed of positive and negative charges, ionic compounds are overall electrically neutral because their charges will cancel out For example… For example… Na +1 will bond with Cl -1 Na +1 will bond with Cl -1 Mg 2+ will bond with O 2- Mg 2+ will bond with O 2- Al 3+ will bond with N 3- Al 3+ will bond with N 3- Two K +1 can also bond with One S 2- Two K +1 can also bond with One S 2-

21 Writing Chemical Formulas Al 3+ S 2- Al 2 S 3 Al 3+ S 2- The numbers on top are the charges, while the numbers on the bottom tell how many atoms there are

22 Practice Write as many compounds as you can with the following ions. Remember that the overall charge must be zero. There are 9 possible. Li +1 Ca 2+ Al 3+ N 3- S 2- Cl -1

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

24 Ionic Bonding When cations and anions transfer electrons, a SALT is formed When cations and anions transfer electrons, a SALT is formed Draw the electron dot structure for the following atoms Draw the electron dot structure for the following atoms Li and Br Li and Br Mg and O Mg and O Two K and One S Two K and One S One Sr and Two F One Sr and Two F

25 When cations and anions form bonds with each other they are called SALTS Example: Example:Li 1s2p F Li + F-F- LiF SALTS

26 Practice Show how the following compounds bond with the use of orbital diagrams 1. NaF 2. MgO 3. Li 2 S 4. CaCl 2 5. AlN

27 Properties of Ionic Compounds Crystalline Solid at Room Temperature Crystalline Solid at Room Temperature High Melting Points High Melting Points Can conduct an electric current when melted or dissolved in water Can conduct an electric current when melted or dissolved in water

28 Section 7.3 – Bonding in Metals Metal atoms are arranged in very compact and orderly patterns Metal atoms are arranged in very compact and orderly patterns

29 Metallic Bond A Metallic Bond is a bond between metal cations surrounded by a sea of electrons A Metallic Bond is a bond between metal cations surrounded by a sea of electrons

30 Metallic Bond The attraction of the free floating valence electrons holds them together The attraction of the free floating valence electrons holds them together

31 Crystalline Structure of Metals (Page 202)

32 Properties of Metals 1. Good Conductors of electrical current 2. Ductile (ability to be stretched) 3. Malleable (ability to be shaped)

33 Alloys Alloys are a mixture of two or more elements, at least one being a metal Alloys are a mixture of two or more elements, at least one being a metal Very few of the metal objects you use everyday are pure metals Very few of the metal objects you use everyday are pure metals Alloys are important because the combination of metals are stronger than the single metal by itself Alloys are important because the combination of metals are stronger than the single metal by itself

34 Examples of Alloy Combinations Brass – copper and zinc Brass – copper and zinc Sterling Silver – silver and copper Sterling Silver – silver and copper Bronze – copper and tin Bronze – copper and tin Steel – iron, carbon, boron, chromium, manganese, molybdenum, nickel, tungsten, vanadium Steel – iron, carbon, boron, chromium, manganese, molybdenum, nickel, tungsten, vanadium Stainless Steel – iron, chromium, carbon, nickel Stainless Steel – iron, chromium, carbon, nickel Cast Iron – iron and carbon Cast Iron – iron and carbon

35 Homework Chapter 7 Assessment Chapter 7 Assessment #’s 30-44, 48, 53, 55, 56, 58, 59, 60, 62, 63, 64, 65, 72, 73, 87, 88, 90, 92, 93, 94, 95

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