Unit 2 NAB Prep Flashcards
Describe in detail the difference between sp3 and sp2 hybridisation
Sp3 hybridisation involves the mixing of one S and three P orbitals whereas sp2 involves the mixing of one S and only two P orbitals
Define the term conjugated system
A conjugated system is the part of a molecules consisting of alternating C to C single and double bonds
Explain how the presence of a conjugated system can give rise to a coloured organic molecule
A conjugated system lowers the energy gap between the HOMO and LUMO. This gap now relates to the coloured part of the electromagnetic spectrum. The colour observed is complementary to the colour of the light absorbed.
State the relationship between the number of C=C in a conjugated system and the colour of a compound
The longer the conjugated system, the larger the wavelength of light (lower frequency absorbed)
Define the term chromophore
Chromophore is a group of atoms within a molecules responsible or the absorption of visible light.
State what is meant by a chiral carbon
Chiral carbon is a tetrahedral carbon with four different groups attached.
Explain what is meant by the term enantiomer
Enatiomer is an optical isomer - a molecules possessing a chiral carbon
What will happen to the light in an equal mixture of both enantiomers?
No rotation
What name is give to the mixture of enantiomers ?
Racemic
Define Homolytic fission
Homolytic fission is when one electron goes to one atom and the other electron goes to the other atom.
Define Heterolytic fission
Heterolytic fission is when both electrons go to the same atom forming ions
What conditions are required for homolytic fission to take place?
Light (U.V.)
Define Nucleophile with examples
Negatively charged ion or neutral molecules that are electron rich Cl-
Define Electrophiles with examples
Positively charged ions or neutral molecules that are electron deficient. H+
Why are secondary carbocations more stable
Secondary carbocation is more stable than primary due to the positive inductive effect of the alkyl groups.
