1 / 54

Chapter 7

Chapter 7. Ionic and Metallic Bonding. Bonding--definition. Bonding attractive forces binding ‘atoms’ or ‘ions’ together to form a cpd (ionic and covalent) attractive forces holding ……. or. Compound. Compound atoms of different elements join together chemically

bijan
Download Presentation

Chapter 7

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 7 Ionic and Metallic Bonding

  2. Bonding--definition Bonding • attractive forces binding ‘atoms’ or ‘ions’ together to form a cpd (ionic and covalent) • attractive forces holding …… or

  3. Compound Compound • atoms of different elements join together chemically • totally different in chem properties from the elements …. • Elements form cpds to increase in stability • Electrically neutral • A + B → A-----B bond Elements cpd • e.g. Na + Cl2 → NaCl

  4. bonding Form cpds Pure metal Intermolecular forces Metallic Bond Van derwaals Forces H bond Ionic bond Covalent bond Ion-dipole Dipole-dipole London dispersion

  5. 2 Types of Bonding—form cpds • Ionic bonding • transfer e- → cations and anions • Metal + nonmetal(s) • Form ionic cpds (e.g. NaCl) • 2. Covalent bonding • share e- (no ions) • Nonmetals only; (e.g. CO2, H2O) • form covalent cpds (molecular cpds)

  6. Compounds Covalent cpds or molecular cpd Ionic cpds formed by formed by Covalent bonds Ionic bonds Sharing e- Transfer of e- Metal + nonmetal(s) nonmetals e.g. MgO e.g. H2O

  7. 2 Types of Bonding— do not form cpds *3. Metallic bonding • in metallic elements • does not form cpds. *4. Hydrogen bonding • between H and O, N, or F atoms (among molecules) • does not form cpds

  8. Valence e- Valence e- • e- in the highest EL of an atoms. • # valence e- largely determines the chem properties of an element.

  9. Valence e- # of valence e- in an atom of (a representative element) = group # or the ones digit of the group #

  10. Valence e- 7.1

  11. The Octet Rule (1) The Octet Rule • Atoms of what type of elements tend to lose e-? metals: groups 1A, 2A, 3A, B • Atoms of what type of elements tend to gain e- ? Nonmetals: groups 5A, 6A, 7A

  12. The Octet Rule (2) In forming cpds, atoms tend to achieve the e- confign of a noble gas.

  13. Ionic Bonding Ionic bonding • transfer e- • Metal + nonmetal(s) • Metals (1A, 2A, 3A, transition) lose e- to form …→ cations • Nonmetals (5A, 6A, 7A) gained e- to form … • cations and anions attract each other → Ionic cpd

  14. Ionic Bonding Cation and anion attract each other by electrostatic force • ioniccpds [metal + nonmetal(s)] • e.g. Na → Na+ + e- (loss) Cl + e- → Cl- (gain) • Na+ ~~ Cl- Electrostatic attraction

  15. Formation of Ionic Cpds Formula Units (ionic cpds) • the lowest whole-# ratio of ions in an ionic cpd. • A chemical formula shows the kinds and #s of atoms in the smallest representative unit of a sub. e.g. NaCl is a formula unit of sodium chloride—1 Na+ bonded to 1 Cl-

  16. The Octet Rule (3) Losing valence e- • Atoms of metals tend to lose their valence e- • leaving a complete octet in the next-lower EL. • e .g. Na (1s22s22p63s1) loses 1 valence e ---- leave a Ne e-confign (1s22s22p6)→ Na+ Neon e- confign

  17. The Octet Rule (4) Gaining e- • Atoms of some non-metals tend to gain e- to achieve a complete octet. • e.g. Cl (1s22s22p6 3s23p5 ) achieve an e- confign of Ar (Cl- 1s22s22p6 3s23p6 ) after gaining 1 e- Ar e- confign

  18. Formation of Cations An atom lost valence e- produces a cation (+ve). e.g. Na → Na+ + e- Mg → Mg 2+ + 2 e- e.g. Al → cations

  19. Formation of Cations cations are produced by • the loss of valence e- from metal atoms. • The e- loss (ionization) of the Na atom Ne e- confign

  20. Formation of Cations The e- confign of the Na+is the same as that of a Ne atom. Na+

  21. Na+ and Ne Differences Similarity • same e- configuration • both octet

  22. Formation of Cations 1 unit of +ve charge 1 unit of –ve charge Na ion

  23. Formation of Cations • A Mg atom attains the e- confign of Neby losing both valence e-. • The loss of valence e- produces a Mg cation(Mg2+) with a charge of 2+. (2 units of –ve charge) (2 units of +ve charge)

  24. Formation of Cations • Cations of gp 1A 1+ • Cations of gp 2A elements 2+

  25. Formation of Anions The gain of e- by a neutral atom → an anion. • A particle derived from an atom (nonmetals) or a group of atoms • Carries -vecharge(s) after gaining e-. • many names of an anion ends in -ide. e.g. oxide, chloride, fluoride, sulfide, nitride, iodide,

  26. Formation of Anions

  27. Formation of Anions • A gain of 1 e- gives Cl an octet and converts a Cl atom into a chloride ion (Cl-). • the same e- confign as the noble gas Ar.

  28. Formation of Anions Both a Cl- and the Ar atom have an octet of e- in their highest occupied ELs.

  29. Formation of Anions In this eqn, each dot in the e- dot structure represents an e- in the valence shell in the e- confign diagram. 7 valence e- Octet

  30. Formation of Anions halide ions • ions produced when atoms of Cl and other halogens gain e-. • Fluorides (F-), chlorides, bromides, iodide • All halogen atoms need to gain only 1 e- to achieve the e- confign of a noble gas.

  31. Formation of Anions • O is in Gp 6A.

  32. Ionic Charges of SomeIons

  33. Anions in Binary Cpds

  34. Polyatomic Ions

  35. Formation of Anions 7.1

  36. Metal Ions with more than 1 Ionic Charges

  37. Highly Unequal Sharing • Ionic Bond • e- transfer results in the formation of 1 +ve ion and 1 -ve ion. • Metal ~ nonmetal • The bond formed by the 2 oppositely charged ions. Cation~~anion Electrostatic attraction

  38. A Model of Bonding • By forming bonds, atoms acquire an octet of e- and the stable e- confign of a noble gas. • Atoms are often more stable when they’re bonded in cpds than when they’re free atoms.

  39. Formation of Ionic Cpds Ionic Bonds • The electrostatic forces that hold ions together in ionic cpds are called ionic bonds.

  40. Physical Properties of

  41. Atomic View of Metallic Bonding • Each atom in this model of a Gp 2 metal releases its 2 valence e- into a sea of e- to be shared by all of the metal atoms. • Delocalized e-

  42. Sea of Valence e- • The valence e- of metal atoms are loosely held by the +vely charged nucleus. • In metallic bonding, metal atoms don't lose valence e-. • Not forming cpds

  43. Sea of Valence e- • metallic bond • Metal atoms release valence e- into a sea of e- shared by all of the metal atoms. • Attraction between e- sea and the metal atoms (cations)

  44. Atomic View of Metallic Bonding • Bonding in metals is not rigid. As a metal is struck by a hammer, the atoms slide thru the e- sea tonew positions while continuing to maintain their connections (bond) to each other. • The same ability to reorganize explains why metals …

  45. Properties That Reflect Metallic Bonding • Conductors of electricity • the valence e- are freely moving and is charged. • Electric current is a flow of e-

  46. Properties That Reflect Metallic Bonding • Metals and alloys are malleable • made into thin sheets

  47. Properties That Reflect Metallic Bonding • Metals are Ductile • can be drawn into wires.

  48. CST problem 1 When cations and anions join, they form what kind of chemical bond? A ionic B hydrogen C metallic D covalent

  49. CST problem 2 The reason salt crystals, such as KCl, hold together so well is because the cations are strongly attracted to A neighboring cations B the protons in the neighboring nucleus C free electrons in the crystals D neighboring anions.

  50. The End

More Related