Chapter 13 Flashcards
what is the bonding in an alkene?
there is a sigma and pi bond
what is a pi bond?
sideways overlap of p orbitals
what does a pi bond do to the C=C bond?
prevents rotation by locking the carbons
diagram showing formation of pi bond
bond angle in a C=C bond is?
120?
what is a sterio-isomer?
compound with the same structural formula but different arrangement of atoms in space
why can E/Z isomerism occur in alkenes?
contains a C=C bond with restricted carbon rotation
and
has different groups attached to each carbon in the C=C bond
what is cis-trans isomerism?
when one of the groups attached to each carbon in the C=C bond is the same
why are alkenes reactive?
they have a localised pi system with the electron density concentrated above and below the plane
means that the pi electrons are more exposed to electrophilic attack
what is stronger sigma or pi bond?
sigma bond
what happens when bromine water is added to an alkene?
it turns from orange to colourless
why can electrophilic addition occur to alkenes?
the C=C bond is a region of high electron density due to the pi electrons
more exposed to electrophilic attack
what is an electrophile?
an electron pair acceptor
outline electrophilic addition
electrophile is polar so has delta +ve and -ve atoms
+ve atom in the electrophile attracts the pi electrons which are exposed which causes the C=C bond to break
bond forms between carbon atom in C-C and the delta +ve atom
the electrophile breaks by heterolytic fission to form a negative ion with an electron pair
negative ion donates electron pair to the carbocation to form a bond
what is a polymer?
large molecules made up of many monomers
