organics - aromatics

Question 1

what does aromatic mean in chemistry

Answer 1

molecules that contain more than one benzene ring

Question 2

what is a benzene ring

Answer 2

a ring with conjugated π systems
-Conjugated π systems arise from alternating double and single bonds in which the electrons are delocalised

Question 3

what is the structure of benzne

Answer 3

• structure consists of 6 carbon atoms in a hexagonal ring, with alternating single and double carbon-carbon bonds
• each carbon atom forms 3 sigma bonds using the sp2 orbital
• the remaning p orbitals overlap laterally with p orbtials of meighbouring carbon atoms to for a π system

Question 4

how can the electrons in benzene be delocalised

Answer 4

-the extensive overlap of p orbitals result in the electrons being delocalised as they can spread over the entire ring - causing a π system

Question 5

what is a π system

Answer 5

-two ring shaped clouds of electron density - one above the plane and one below

Question 6

what is the shape of benzene and its bond angles

Answer 6

trigonal planar - 120

Question 7

what does the delocalisation of electrons cause the bonds to be

Answer 7

identical
-single and double bond character
-bond are all the same length
-140 pm