Rules for Drawing Lewis Diagrams by dffhrtcv3


									Rules for Drawing Lewis Diagrams
1. Determine how many e- will be in drawing
2. Determine the central atom
   –   Least electronegative element
   –   Needs most e- for octet
   –   Has fewest valence e-
   –   First listed in formula (not always!)
   –   NEVER H!
3. Connect atoms with covalent bonds (2 e-)
4. Add electrons to all atoms to get octet
5. Count and check
   –   Does the number of e- in drawing equal the number of e-
    Rules for Drawing Lewis Diagrams
                 Part II
•  Follow steps 1-5 from before
•  IF the answer to question 5 is NO, go to rule
   6 (below)
6. More e- in drawing than calculated?
    – Erase unshared pair
    – Draw double bond (never on H or halogens)
    – Erase another unshared pair from other atom in
      double bond
•   Count and check

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