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Chapter 7 Ionic and Metallic Bonding. Ms. Wang Lawndale High School. Section 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.
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Chapter 7Ionic and Metallic Bonding Ms. Wang Lawndale High School
Section 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 Valence Electrons Example: How many electrons are in the valence shell of sodium? Step 1: Write the electron configuration of sodium Na = [Ne]3s1 Step 2: Count the number of electrons in the valence shell (outermost shell).
Determine the Valence electrons in each of these elements • K 6. Be • P 7. Li • C 8. He • O 9. Ne • N 10. B
Electron Dot Structure • Diagrams that show valence electrons as dots 3 5 PRACTICE 1. K 6. Be 2. P 7. Li 3. C 8. He 4. O 9. Ne 5. N 10. B X 2 6 1 8 4 7
Octet Rule • Eight electrons in the highest occupied energy level just like the noble gases (except He) • Metal elements lose their valence electrons • Nonmetal elements gain electrons
Formation of Cations 3s 2p 2s 1s Sodium atom Na Sodium ion Na+ Neon atom Ne Na Na+ + e-
Formation of Anions 2p 2s 1s Fluorine atom F Fluorine ion F- Neon atom Ne F + e- F-
Practice • Show how a Lithium atom becomes an cation 2. Show how a Calcium atom becomes a cation 3. Show how a Chlorine atom becomes an anion 4. Show how an Oxygen atom becomes an anion
Bonding • Once an atom has a stable octet, it is happy and doesn’t want to react anymore • Atoms without stable octets, are sad and want to react with another element to achieve a stable octet • Gain or Lose Valence Electrons Complete this sentence: Noble Gases do not easily form bonds because….
Why do atoms form bonds?To be more chemically stable and less reactive How do atoms become more chemically stable and less reactive? • By having completely filled s and p orbitals just like the noble gases
Section 7.2 – Ionic Bonds • Ionic Compounds – metal cations and nonmetal anions that are held together by electrostatic forces • Although ionic compounds are composed of ions, they are electrically neutral
Ionic Bonding • An ion is an atom that has gained or lost one or more electrons and thus have an electrical charge. • To find the charge of the ion subtract the number of electrons from the number of protons. Example: [S]=1s22s22p63s23p4 (16 p+, 16e-) [S2-] 1s22s22p63s23p6 (16p+, 18e-) 16 -18 = -2
Labeling the Periodic Table These elements have the following charges: Group 1A = 1+ Group 2A = 2+ Group 3A = 3+ Group 4A = 4+ or 4- Group 5A = 3- Group 6A = 2- Group 7A = 1-
SALTS When cations and anions form bonds with each other they are called SALTS • The + and - charges that cations and anions have causes an attraction between the two • They come together to form an ionic bond also known as a salt. Example: Na+ Cl- NaCl
SALTS When cations and anions form bonds with each other they are called SALTS • Example: Li 1s 2p F 1s 2p Li+ LiF F-
Practice Show how the following compounds bond with the use of orbital diagrams • NaF • KBr • MgO • Li2S • CaCl2 • AlN
Ionic Bonds • Ionic bond is typically a bond between a METAL CATION and a NONMETAL ANION • The electrostatic forces between the two types of ions hold them together • Bonds form when metals donate electrons to nonmetals
Properties of Ionic Compounds • CrystallineSolid at Room Temperature • High Melting Points • Can conduct an electric current when melted or dissolved in water
Section 7.3 – Bonding in Metals • Metallic bond is a bond between metal cations. • The attraction of the free floating valence electrons for the positively charged metal ions hold them together.
Crystalline Structure of Metals • Metal atoms are arranged in very compact and orderly patterns • Physical Properties of Metals • Good Conductors of electrical current • Ductile - can be drawn into wires • Malleable – can be hammered or shaped • Alloys – mixtures composed of two or more elements, at least one being a metal
Homework 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