2 peripheral Lewis’ bonded to a central LewisSkeletal structuresSkeletal structures• Because there are exceptions to the octet rule, we need a set of rules to determine how many electrons surround atoms• The first step is to determine how the atoms are bonded in a molecule• Generally, if there is only one of one element and multiple copies of another element, the unique element is central• Commonly, H is peripheral, bonded to O• Read 7.6 (pg. 236) up to PE5. Do PE5.Counting total electronsCounting total electrons• Once we have determined the basic structure of the molecule we can start placing electrons around atoms• The first step is to determine the total number of electrons that are available• We use the group number of an element to indicate the number of valence electrons that it contributes to the molecule.• E.g. O in group VIA (6A), contributes 6 e–s• Read 7.6 (pg. 237) up to PE6 (including example). Do PE6.
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