Chemistry
Chemistry
Problem
Some molecules do not follow the octet rule, and so, have fewer than eight electrons in their valence shell. Draw the Lewis structures for each of the following molecules: a. a b. b c. cIntuitive explanation
These molecules break the octet rule because they're stable with incomplete valence shells—a key exception you'll encounter often. The trick is to place the fewest electrons needed to form bonds and satisfy the atoms' basic bonding requirements, rather than forcing eight electrons everywhere. Start by counting total valence electrons, then build single bonds first, and stop when all atoms have at least a duet (two electrons for hydrogen) or the minimum stable arrangement. You'll notice boron and beryllium compounds are common culprits here.
Intuitive explanation
These molecules break the octet rule because they're stable with incomplete valence shells—a key exception you'll encounter often. The trick is to place the fewest electrons needed to form bonds and satisfy the atoms' basic bonding requirements, rather than forcing eight electrons everywhere. Start by counting total valence electrons, then build single bonds first, and stop when all atoms have at least a duet (two electrons for hydrogen) or the minimum stable arrangement. You'll notice boron and beryllium compounds are common culprits here.