Organic lecture 1

Question 1

Briefly describe covalent bonding

Answer 1

Covalent bonds form most of the bonds in organic compounds. When forming covalent bonds, atoms tend to attain a noble gas configuration

Question 2

State the three things to consider when looking at how covalent bonds form

Answer 2

• The total number of electrons in an atom
• The number of electrons in the outer shell
• The valency (ie the number of bonds)

Question 3

Define alkynes

Answer 3

A homologous series containing at least one carbon-carbon triple bond

Question 4

Define allenes

Answer 4

Compounds in which one carbon atom is double bonded to two other carbon atoms

Question 5

Define the node/nodal plane

Answer 5

An area of low electron density

Question 6

Describe how to count electrons for any atom in a molecule

Answer 6

The purpose is to determine how many electrons the atom owns in the molecule compared to how many it owns as an isolated atom. It owns one electron per bond and two per lone pair

Question 7

Describe s orbitals

Answer 7

S orbitals are spherical

Question 8

Describe p orbitals

Answer 8

P orbitals are dumbbell shaped with a node in the middle. There are three p orbitals, labelled x y and z and they are superimposed at 90 degrees to eachother.

Question 9

Describe hybrid orbitals

Answer 9

When bonds are formed, various combinations of s and p orbitals give hybrid orbitals, which define the shapes of molecules

Question 10

Describe sp3 hybridisation

Answer 10

One s and three p orbitals mix to form four identical sp3 hybrid orbitals. Each orbital is dumbbell shaped with one lobe smaller than the other, and the four have corners forming a tetrahedron, and are 109.5 degrees apart from each other

Question 11

Describe the bonding in methane

Answer 11

Each sp3 hybrid orbital forms a sigma bond (a region of high electron density) with a hydrogen atom.