Electronic Effects

Question 0

What is an sp2 bond?

Answer 0

Double bond.
Trigonal planar.
Medium sized tail and a larger electron density than sp3.

Question 1

What is an sp3 bond?

Answer 1

Single bond.
Tetrahedral structure.
Largest tail but the least electron density.

Question 2

What is an sp bond?

Answer 2

Triple bond.
Linear shape.
Smallest tail but the largest electron density.

Question 3

What is a sigma bond?

Answer 3

Symmetric.

Only one can be formed between two atoms because otherwise you would get bent bonds.

Question 4

What is a pi bond?

Answer 4

Double bond.
Not symmetric.
Can form more than one, they are stronger than sigma bonds

Question 5

What are bonding orbitals?

Answer 5

Covalent interaction between two atoms = overlap.
Lots of electron density around orbital nuclei
Add the two atoms together

Question 6

What are anti-bonding orbitals?

Answer 6

Located outside the region of two distinct nuclei.
Loss of electron density around the whole nuclei
Subtract one atom from the other

Question 7

What is the difference between major and minor contributors?

Answer 7

Minor: Charge on carbon
Major: Charge on oxygen- this is more favourable as oxygen is more electronegative than carbon. More stable and resemble the actual structure more than the minor.

Question 8

Name some groups that stabilise anions.

Answer 8

Carbonyl groups
Aldehydes
Ketones
Esters ad acids
Nitro

Question 9

Name some groups that stabilise cations.

Answer 9

Methoxy and amino

Any group with a spare pair of electrons

Question 10

In hybridisation, the electron is first promoted from where and to? When can this not happen?

Answer 10

From 2s to 2p.
This cannot happen when there isn’t a free orbital in the higher state. It is more stable therefore to keep 2 electrons in the lower 2s state than have 2 electrons in a higher state.

Question 11

The chance of an electron being in the overlap between fluorine and hydrogen is larger than that of carbon and hydrogen. Why?

Answer 11

The overlap in fluorine and hydrogen is large in comparison to their size. The carbon hydrogen bond overlap is much smaller in comparison to their size.

Question 12

Is oxygen or nitrogen more electronegative?

Answer 12

Oxygen.

Question 13

What is resonance and why does it occur?

Answer 13

It is the delocalisation of electrons within a molecule.It gives the molecule extra stability, for example benzene has a ring is delocalised electrons and is very stable. The canonical structure is lower in energy than the other structures of that molecule.

Question 14

The bent geometry of a water molecule is due to which factor?

Answer 14

Non bonding pairs of electrons are repulsed.

Question 15

Sp2 hybridisation requires the mixing of which orbitals?

Answer 15

One s orbital and two p orbitals

Question 16

Sp hybridisation is the mixing of what orbitals?

Answer 16

One s orbital and one p orbital

Question 17

Sp3 hybridisation is the mixing of what orbitals?

Answer 17

One s orbital and three p orbitals

Question 18

Resonance can only happen with what kind of compounds?

Answer 18

Conjugated. (alternating double and single bonds)

Question 19

Why is the deprotonation of ethanol easier than that with ethane?

Answer 19

Ethanol contains an oxygen, oxygen likes being negative so it is easier to remove the hydrogen from it.

Question 20

Why are sigma bond electrons not involved in resonance?

Answer 20

The molecule would fall apart. Resonance systems are sp2 hybridised and requires the overlapping of p orbital.
However, atoms can change their expected hybridisation in order to participate in resonance. (sp3 -> sp2)