04. Alkenes

What does a C=C bond give?

Gives an area of high electron density and alkenes are open to attack by electrophiles

What are alkenes in chemistry?

They are useful starting materials

Describe the double bond of an alkene?

Has 2 different types of bonds: sigma bond and pi bond

What are the C-C and C-H single bonds? How are they formed?

Sigma bonds, formed by overlap of S and P orbitals

What does carbon usually like to do?

Bond to 4 other atoms covalently with sigma bonds

What does carbon bonding to 3 other atoms form?

A pi bond

Give an example of how a pi bond is formed?

When carbon bonds to 3 atoms

Draw the formation of a pi bond

Yes

Why is carbon able to bond to 3 other atoms creating a pi bond?

Normally one 2s² electron is promoted to empty 2p orbital, allowing carbon to make 4 bonds

What occurs in ethene?

Only 3 orbitals become hybridised allowing the pi bond to be formed from the sideways overlap of 2p orbitals

Draw ethene orbitals stuff?

Yes

What does the pi bond cause?

Introduces area of high electron density

What does the pi bond do structurally?

Sticks out above and below the rest of teh molecule

What does the pi bond sticking out cause it to be?

Makes it negative and attacked by electrophiles, making alkenes useful starting points for making organic compounds