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Chapter 1 Activity 8

Sodium chloride. Nitrogen dioxide. Chapter 1 Activity 8. Carbon monoxide. Hydrochloric acid. Calcium fluoride. How Atoms Interact with Each Other. Magnesium sulphate. Hydrogen peroxide. Na. F. 2 8 1. 2 7. Why Do Elements Form Compounds?. to become stable The Octet Rule:

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Chapter 1 Activity 8

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  1. Sodium chloride Nitrogen dioxide Chapter 1Activity 8 Carbon monoxide Hydrochloric acid Calcium fluoride How Atoms Interact with Each Other Magnesium sulphate Hydrogen peroxide

  2. Na F 2 8 1 2 7 Why Do Elements Form Compounds? to become stable The Octet Rule: Atoms tend to gain or lose electrons during chemical reactions so that the atoms have a filled outer energy level (usually 8 electrons). Lose 1 electron Gain 1 electron

  3. How do we show bonding between atoms? We show bonding using: electron-dot diagrams or Lewis Dot Diagrams

  4. Lewis Dot Diagrams Each dot represents a valence electron Now practice writing the Lewis Dot for elements in the third period

  5. Try this!!! Practice determining the number of valence electrons in an atom Practice writing the Lewis diagram for atoms 1-20.

  6. Is it still an atom? • Atoms are neutral- protons = electrons • After electrons are lost or gained, they are no longer atoms. THEY ARE NOW IONS!!!

  7. Ionic Bonds • Exist between a metal & nonmetal • Metals want to lose their valence electrons • And become Cations (+) • Nonmetals want to gain more valence electrons • And become Anions (-) • Why……. To become stable

  8. IA VIIIA IIA IIIA IVA VA VIA VIIA -4 +4 -3 -2 -1 +1 +2 +3 Which elements lose and gain electrons?

  9. So… A Metaland a Nonmetal get together! But remember, they get together to get a filled outer energy level And that is the octet rule

  10. FORMATION OF IONIC BONDS IONIC BONDS: • Electrons are transferred from a metal to a nonmetal • The metal becomes a cation; the nonmetal becomes an anion. • The attraction of the oppositely charged ions forms the ionic bond. • http://www.kentchemistry.com/links/bonding/bondingflashes/bond_types.swf • http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf • https://www.youtube.com/watch?v=bK9nMHTLhmk

  11. Naming Ionic Compounds

  12. Ionic Compounds • Attraction between a metal cation (M+) and a nonmetal anion (X-) • M+ X- • Charges on ions must add up to zero!

  13. Naming an Ionic Compound: 1. Write the name for the metal and nonmetal 2. Change the nonmetal ending to IDE Ex: NaCl sodium chloride

  14. carbide nitride phosphide oxide sulfide fluoride chloride bromide iodide

  15. EXAMPLES: potassium bromide sodium oxide magnesium sulfide calcium nitride aluminum fluoride

  16. Writing Ionic Compounds

  17. How to Write an Ionic Formula: 1. Write down symbols 2. Determine Ionic Charges 3. Charges must cancel each other out (equal zero) • if not, use criss-cross method to form subscripts to cancel out charges

  18. K+1 Br-1 charges cancel KBr EXAMPLES: Mg+2 O-2 charges cancel MgO Al+3 N-3 charges cancel AlN Mg+2 Cl-1 charges DON’T cancel criss-cross MgCl2 Na+1 S-2 charges DON’T cancel criss-cross Na2S

  19. Potassium Bromide K+1 Br-1 charges cancel KBr Magnesium Oxide Mg+2 O-2 charges cancel MgO EXAMPLES: Aluminum Nitride Al+3 N-3 charges cancel AlN Magnesium Chloride Mg+2 Cl-1 charges don’t cancel, criss-cross MgCl2 Sodium Sulfide Na+1 S-2 charges don’t cancel, criss-cross Na2S Aluminum Oxide Al+3 O-2 charges don’t cancel, criss-cross Al2O3

  20.                                             Ionic Bonds: One big greedy thief dog! Ionic bonding can be best imagined as one big greedy dog steeling the other dog's bone. 

  21. Lewis Dot DiagramsIonic Bonds Li Li Li Li Li • • • • • • • • • • • • • • • • • • • • F F F F F • • • • • • • • • • • • • • • • • • • • • • • • Li • F • • • -1 +1 Li F 2 2 8 Li F 2 1 2 7 by giving or taking electrons with other atoms. Each atom attempts to attain a filled outer energy level +1 -1

  22. • • • • +1 -1 • • • Li F • Count around Fluorine, there are 8 dots (8 valence electrons to make it stable)

  23. • • • • +1 -1 • • • Li F • -1 +1 Li F 2 2 8 What is an Ion? • A charged atom • Becomes charged after it loses or gains electrons • It has a charge because the number of protons and electrons are no longer equal P=3 E=2 P=9 E =10

  24. • • • • Li F • • • • Bonding & Non-bonding Electrons • Bonding electrons-are the 2 electrons that form the bond between the atoms • This can be represented with a dash Bonding electrons

  25. • • • • Li F • • • • Bonding & Non-bonding Electrons • Nonbonding electrons-are any electrons that DO NOT form the bond between the atoms. • They are in pairs (here there are 3 pairs of nonbonding electrons Nonbonding electrons

  26. Chapter 1Activity 8 Covalent Bonding

  27. What is an Ionic Bond? IONIC BONDS: 1. Give or Take (transfer) valence electrons 2. Occur between a metal & nonmetal 3. High melting points 4. Conducts electricity when in solution EX: NaCl MgCl2

  28. What is a Covalent Bond? COVALENT BONDS: 1. Share valence electrons 2. Occur between nonmetal atoms only 3. Low melting point 4. Don’t conduct electricity when in solution EX: H2O Cl2 http://www.pbslearningmedia.org/asset/lsps07_int_covalentbond/

  29. COVALENT VS. IONIC BONDS

  30. • • • • • • • • • • • • • • • H H H H H F F F F F • • • • • • • • • • • • • • • • • • • • • • • • • • • • • H F • • • • Lewis Dot Diagramsfor Covalent Bonds by sharing electrons with other atoms. Each atom attempts to attain a filled outer shell (typically a noble gas electron configuration)

  31. • • • • • H F • • • H F • • • • • • Structural Formulas Bonds are represented with a dashed line Circle all bonded electron pairs Lewis dot Diagram 1 single covalent bond (1 shared pair of e-s) 3 unshared pairs of e-s Structural Diagram

  32. Covalent Bonds: Dogs of equal strength. Covalent bonds can be thought of as two or more dogs with equal attraction to the bones.  Since the dogs (atoms) are identical (same electronegativities), then the dogs share the pairs of available bones evenly. 

  33. Naming Covalent Compounds Ex: COCO2 1. The first element’s name doesn’t change. carbon carbon 2. Second element ends in IDE carbon oxide carbon oxide 3. Use prefixes to distinguish between compounds & to show how many atoms of each element are present carbon monoxide carbon dioxide

  34. Prefixes for Molecular Compounds: 1. drop vowel on prefix if element starts with vowel EX: monooxide = monoxide 2. Don’t drop vowel for di and tri prefixes

  35. nitrogen monoxide nitrogen dioxide EXAMPLES: dinitrogen monoxide dinitrogen trioxide phosphorus pentachloride carbon disulfide sulfur hexafluoride

  36. How to Write a Molecular Formula: • Write down element symbol • Prefixes give you what subscripts to use Ex: Carbon tetrachloride Sulfur trioxide Tetraiodine nonoxide Ex: Carbon tetrachloride Sulfur trioxide Tetraiodine nonoxide Ex: Carbon tetrachloride Sulfur trioxide Tetraiodine nonoxide Ex: Carbon tetrachloride Sulfur trioxide Tetraiodine nonoxide CCl CCl4 SO SO3 I O I4O9

  37. Warm-up • Name the following: • P2O5 • C3H8 • K2O • Cl2O7 • Al2O3

  38. How to review for a quiz or test • 1. create study checklists • 2. create summary notes • Organize your notes (graphic organizers) • Create Flashcards • Form study groups • Create possible test questions.

  39. ???? Bond Energies

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