2. metals: lose valence electrons –form cation –form cation (+ ion) non-metals: gain electrons anion –form anion (- ion)

3. Ionic Bond occurs between: metalnon-metal element metal element & non-metal element involves transfer of electrons between metal & non-metal elements to form ionsinvolves transfer of electrons between metal & non-metal elements to form ions # electrons lost by cation(s)# electrons lost by cation(s) = # electrons gained by anion(s) = # electrons gained by anion(s)

4. Metals are Losers! Na atom configuration: 2-8-1 Na loses 1 electron → Na +1 ion –Na +1 configuration is 2-8 same as Ne configuration (2-8)

5. Na metal 

6. take elements from what group _?_ will easily take the one valence electron from Na?? what group has 7 valence electrons so only need one more? group 1 elements will easily give up their one valence electron to the elements in group 17

7. Non-metals are Winners! Cl configuration: 2-8-7 Cl gains 1 electron → Cl -1 ion –Cl -1 has the configuration 2-8-8 same as Ar configuration (2-8-8)

8. Cl 2 (g) 

9. electron transferred from Na to Cl

11. Structure of Ionic Compounds oppositely charged ions are attracted to each other by strong electrostatic interactions (+/-) (+/-) ions form crystal lattice – regular 3-D pattern or array – ions held in fixed positions (solid state) Unit Cell = smallest repetitive unit in lattice

12. lattice structure  NaCl has its own unique properties

13. The more Na and Cl 2, the larger the resulting crystal of NaCl will be NaCl will be

14. different representations of a crystal lattice

15. Lewis Diagrams for Ionic Compounds Lewis structure for NaCl shows ions: [Na] +1 [ Cl ] -1 [Na] +1 [ Cl ] -1 remember: Lewis diagrams show valence electrons!

16. Predicting Ionic Compounds What is the ionic compound formed from calcium and iodine?What is the ionic compound formed from calcium and iodine? calcium: metal with 2 valence electrons calcium: metal with 2 valence electrons - loses both electrons  [Ca] +2 - loses both electrons  [Ca] +2 iodine: non-metal with 7 valence electrons iodine: non-metal with 7 valence electrons - gains 1 electron  [ ‍ I ] -1 - gains 1 electron  [ ‍ I ] -1 how many iodine ions are needed to make a neutral compound? how many iodine ions are needed to make a neutral compound?2

17. Lewis Diagram of calcium iodide (CaI 2 ) [Ca] +2 [:I:] -1 [:I:] -1 or or [:I:] -1 [Ca] +2 [:I:] -1 note: total charge MUST add up to zero since compounds are neutral since compounds are neutral ·· ·· ·· ·· ······ ··

18. Properties of Ionic Compounds high melting points low vapor pressures tend to be hard and brittle solids do not conduct electricity molten (liquid) states do conduct electricity aqueous solutions do conduct electricity

19. #1: transfer of e - from metal to non-metal atoms: IONS form #2: electrostatic attraction between +/- ions leads to ionic bond