Curly arrows
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What is activation energy?
The energy needed to overcome the charge/charge repulsion between molecules
What are the two things that bring molecules together?
Charge/charge attraction between anions and cations and dipoles&dipoles Orbital overlap
When is there a drop in energy with orbital overlap? What does this drop cause?
When there is inphase overlap Bonding orbital The drop helps to bring the molecules together
what else do orbitals control?
The orientation of reactions
What is a nucleophile?
Electron donor
What do nucleophiles have?
Pair of electrons in a filled orbital which is available to donate
What is an electrophile?
Electron acceptor
What do electrophiles have?
Low-lying empty orbital which can be filled by the electrons
Where are electrons transferred to and from in reactions?
From the nucleophile to the electrophile
Which orbital of a nucleophile contains the highest energy electrons?
HOMO
Which orbital of an electrophile is the easiest to transfer electrons to?
LUMO
Which favourable overlap leads to a reaction?
Between the homo of the nucleophile and the LUMO of the electrophile
What do curly arrows show?
Movement of electrons
When are double headed arrows used?
Shows the movement of 2 electrons Used when a process involves bonds being broken heterolytically
What does heterolytically mean?
Both electrons go in the same direction
What is homolysis?
Each atom receives one electron fishhook arrows are used and it produces radicals with unpaired electrons
Where does the base of a curly arrow always come from?
From the nucleophilic species
What type of bonds are good sources of electrons?
Pi bonds
What must curly arrows clearly show?
All the bonds that form All the bonds that break All changes in charge
What does no curly arrow mean?
No change to that part of the molecule
What is the benefit of using curly arrows?
They help us to understand and predict reaction mechanisms
How many electrons is maximum on a 2nd row element?
8 - dont exceed this
What do you do if you give electrons to an atom which is ‘full’?
You have to take some away
When can you make a bond to an atom without breaking another?
When the atom has less than a full shell of e-