Systematic Organic Chemistry- Hydrocarbons Flashcards
If the overlap of a covalent bond is along the axis it is called a
End on SIGMA bond
When is a covalent bond formed
When two half filled orbitals overlap
If orbital lie perpendicular to the bond and overlap they are
Side on PI bonds
The more multiple bonds the more
PI binds are present
What bond is stronger
Sigma bonds are stronger than PI bonds
What is hybridisation
Process of mixing atomic orbitals on an atom to generate a set of new atomic orbitals called HYBRID ORBITALS
Bonding in alkanes with 3 2P orbitals and 1 2s
Form to four degenerate hybrid orbitals
Sp^3 hybrids and point to corners of tetrahedron to minimise repulsion
Later develop sigma bonds
In alkenes when 2s and 2 of the 3 2p orbitals
Form sp^2 hybrid orbitals which adopt a trigonal planar arrangement
Later forms sigma bonds and PI bonds
Why are alkenes unreactive
Due to the non polar nature of bonds
Alkanes react with halogens in sunlight make halogenoalkanes
Example of substitution- reaction in which atom or group of atoms in a molecule replaced by another group of atoms
What kind if reaction is a substitution between an alkali and halogen
Chain reaction with 3 stages
Initiation
Propagation
Termination
What is homolytic fusion in initiation
Using UV light to provide energy to break bonds and split mols into atoms
Occurs with little or no polarity in bonds
What are radicals
E ample chlorine atoms
Are atoms or groups of atoms with unpaired electrons
Extremely unstable and highly reactive
Produced by initiation step
What happen in propagation
Radicals attack other reactant mol removing hydrogen to for other radicals of different kinds
Propagating or sustaining chain reaction
Radical represented by dot
Explain the termination step
As the number of radicals build up collisions occur and stable mols are produced
Radicals used up and not produced
Chain reaction to an end