Bell Work

1. Bell Work • What charges will each of the following have? Cl Na Ca P S F Li Br K O

2. Physical Science – Lecture 40 Drawing Electron Dot Structures for Compounds

3. Electron Dot Structures for Compounds • Electron dot structures for compounds can show the movement of electrons. • For ionic compounds, one arrow movement shows an electron that is given away. • For covalent compounds, connecting the dots shows the two electrons that are shared.

4. Drawing Electron Dot Structures for Compounds • Step 1 – Draw each elements individual electron dot structure. • Step 2 – Determine if each element is a non-metal or metal.

5. If at least 1 is a Metal: • Step 3 – Using single ARROWS, take the electrons from the metal and move them to the non-metal(s). • If the shells are still not full, add more of the metal to create more electrons. • If there are extra electrons on the metal, add more of the non-metal to allow the metal to give its electrons away. • Step 4 –Write the charges of each element after all elements have 8 or 0 electrons left. • Step 5 – Write the chemical formula for the compound if it was not given in the question.

6. If ALL elements are Non-Metals • Step 3 – Connect all the single-electrons sides of each element with single-electron sides of other elements. • Step 4 – Where electrons are shared, draw in the covalent bonds between each set of shared electrons. • Step 5 – Write the chemical formula for the compound if it was not given in the question.

7. Special Rule • All the elements in one compound must be included as one compound. You cannot make two separate compounds.

8. Example • Calcium and Oxygen

9. Example • Nitrogen and 3 Fluorines

10. Example – Single Bonds • Carbon and 4 Hydrogens

11. Example - Double Bonds • Carbon and 2 Oxygens

12. Example – Triple Bonds • Nitrogen and Nitrogen

13. Example Question • The following elements want to react: Sodium and Chlorine • What type of bond will they form? • If ionic, which is the cation and anion? • What does the electron dot structure look like for this compound? • What is the chemical formula?

14. Example Question • The following elements want to react: Flourine and Hydrogen • What type of bond will they form? • If ionic, which is the cation and anion? • What does the electron dot structure look like for this compound? • What is the chemical formula?

15. Example Question • The following elements want to react: Potassium and Sulfur • What type of bond will they form? • If ionic, which is the cation and anion? • What does the electron dot structure look like for this compound? • What is the chemical formula?

16. Turning Electron Dot Structures into Bonds • When electrons are shared, covalent bonds are formed. • Covalent bonds are written as a single line between two elements. • They represent two electrons for each element (because they are shared).

17. Example – MgF2

18. Example – CF4

19. Example – Magnesium Bromide

20. Practice - NaCl

21. Practice – K2O

22. Practice – CH4

23. Practice – Potassium Chloride

24. Practice – CaCl2

25. Practice – H2O

26. Practice – C2H6

27. Practice - CH3OH

28. Practice – NH3

29. NH2CH3

30. Practice – CF2Br2

31. Practice – N2

32. Practice - C3H8

33. Practice - C3H6

34. Practice – Sodium Oxide

35. Practice – C2H2

36. Practice – CaBr2

37. POP QUIZ • Draw the electron dot structure for each of the following: • If you create positive or negative ions, label them as such. • Show the movement of electrons for each one either with arrows or lines.

38. 1. H2O

39. 2. C2H6

40. 3. K2O