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Catalyst – March 8-1, 2010

Catalyst – March 8-1, 2010. Monday Mystery Element! (write it on Monday) This element is easily magnetized. It is important for human nutrition by preventing anemia. Can become radioactive and emit gamma rays (can treat cancer). Catalyst – March 8-1, 2010. Monday Mystery Element!

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Catalyst – March 8-1, 2010

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  1. Catalyst – March 8-1, 2010 Monday Mystery Element! (write it on Monday) • This element is easily magnetized. • It is important for human nutrition by preventing anemia. • Can become radioactive and emit gamma rays (can treat cancer).

  2. Catalyst – March 8-1, 2010 Monday Mystery Element! • This element is easily magnetized. • It is important for human nutrition by preventing anemia. • Can become radioactive and emit gamma rays (can treat cancer). COBALT!

  3. Today’s Agenda • Catalyst • Intro to Covalent Compounds • Covalent Bond Formation (more LDS’s!) • Exit Question

  4. Today’s Objectives • SWBAT describe properties of covalent compounds. • SWBAT model single covalent bond formation.

  5. Covalent Compounds in da House! • Covalent compounds are EVERYWHERE! • Household cleaners (Ammonia) • Water! • Salad dressing • Political debate! (think greenhouse gases)

  6. Find the Characteristics of Covalent Compounds…. Let’s HUNT!

  7. Properties of Covalent Compounds Key Point #1: Properties of covalent compounds: • Electrons are shared • Bonds between nonmetals • Usually gases at room temperature (not crystals) • Low melting points • Poor conductors of electricity (usually not soluble in water)

  8. What’s the difference between ionic and covalent compounds? • It is important to understand the differences between ionic and covalent compounds • Let’s review ionic compound characteristics…

  9. Characteristics of Ionic Compounds • Electrons are transferred • Bonds between metals and nonmetals • Solids, make crystals • High melting points • Good conductors of electricity when dissolved (usually soluble in water)

  10. Double Bubble Group Race! • Each group will complete a Double Bubble Diagram…liiiiiike this (Double Bubble doc) • Rules: • No talking or sharing of notes! • First person fills in ONE bubble and passes paper to next person – cannot skip people! • If next person doesn’t know an answer, he/she must stand up and do 3 “I’m a Chemistry Scholar” jumps before passing paper. • Next person fills in ONE bubble and passes paper to next person…etc!

  11. How do covalent bonds form? • Let’s look at Lewis Dot Structures again! • Key Point #2: Each atom in a compound satisfies the octet rule. This is shown in a Lewis Dot Structure.

  12. Valence Electrons and Number of Bonds…. • Key Point #3: The number of single valence electrons in an atom’s Lewis Dot Structure determines the number of bonds it will make with other atoms in chemical bonds.

  13. Examples…LDS  # Bonds • Potassium (K) • Nitrogen (N) • Chlorine (Cl) • Aluminum (Al) • Barium (Ba) • Carbon (C)

  14. Rules for Drawing Covalent LDS • Count the number of valence electrons you have to work with (can draw individual LDS). • Put the least electronegative atom in the center (except H). • Use pairs of electrons to form bonds between atoms. • Use remaining electrons to complete octets. • If you run out of electrons, introduce multiple bonds to get octets. • To finish, draw bonds as lines (2 dots per line).

  15. Single Bonds • Single covalent bond: one pair of shared electrons (two electrons) • Atoms may be the same • H2, F2, Cl2, Br2, I2, O2 • Atoms may be different • HF, HCl, HBr, HI =

  16. Formation of Single Covalent Bonds Examples H2 F2 HCl (chlorine)

  17. Formation of Single Covalent Bonds Your Turn! Cl2 HBr

  18. Tricks! • Central atom: in the center of a molecule, usually has lower electronegativity • Terminal atom: not in the center of a molecule Hydrogen will NEVER be a central atom!

  19. Formation of Multiple Single Bonds Examples NH3 SeCl2

  20. Formation of Multiple Single Bonds Your Turn! NF3 CH4 CH3Cl

  21. Draw the Lewis Dot Structures for the covalent compounds to the right  Br2 HI PH3 H2S CCl4 PH3 SiH4 Practice Time!

  22. DHMO Article • Read the article SILENTLY AND INDEPENDENTLY • Then, write a letter to Mr. Manny Jambo about your reaction to the article. • Finish letter for homework.

  23. Homework Tonight • Lewis Dot Structure Breakdown • DHMO Letter!

  24. Exit Question • What are 3 characteristics of covalent compounds? • What is one difference between ionic and covalent compounds? • Draw the Lewis Dot Structure for chlorine gas, Cl2.

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