Bonding

Question 1

Principle quantum number

Answer 1

n- corresponds to the energy level (which shell )of an electron - essentially a measure of size
The smaller the n value the closer the closer the orbital is to the nucleus
.n can be and value from 1 to infinity

Question 2

Azimuthal quantum number

Answer 2

l- which sub shell
Can be any value from 0 to n-1
0,1,2,3 correspond to s,p,d,f
Energy increased as the azimuthal quantum number increased

Question 3

Magnetic quantum number

Answer 3

ml - describes the orbitals within a subshell

Can be any value from -l to +l

Question 4

S orbital

Answer 4

Spherical ,symmetrical and centred around the nucleus

Question 5

P orbital

Answer 5

Composed of 2 lobes located symmetrically about the nucleus and contain a node where the probability of finding an e- is 0
Dumbbell shaped and can be lined up on the x, y or z axis

Question 6

D orbital

Answer 6

Composed of four symmetrical lobes and contains 2 nodes

Four are clover shaped and fifth looks like a donut wrapped around the centre of the p orbital

Question 7

Spin quantum number

Answer 7

ms - each orbital contains 2 electrons each with a different spin +1/2 or - 1/2

Question 8

Molecular orbitals

Answer 8

Combined atomic orbitals - add or subtract wave functions

Question 9

If signs of the wave functions are the same

Answer 9

They form a bonding orbital which is more stable and in a lower energy state

Question 10

If the signs of the wave functions are different

Answer 10

We get an antibonding orbital which has higher energy and is less stable

Question 11

Head to head or tail to tail overlap of orbitals forms

Answer 11

Sigma bonds

All single bonds are sigma bonds - stronger than individual pi bond - free rotation of atoms

Question 12

Pi bond

Answer 12

When two p orbitals are parallel - side by side - and their electron clouds overlap

Question 13

Describe bonding strength and length or single double and triple bonds

Answer 13

Single bond is longer and weaker than a double or triple bond
Double bond is a sigma plus pi bond and is shorter and stronger than single
Triple bond is a sigma bond and 2 pi bonds which is stronger and shorter than both
— a single sigma bond is stronger than an individual pi bond —-

Question 14

What is the orbital electron configuration of carbon ? Of carbon as an octet?

Answer 14

1s’2 2s’2 2p’2

As octet: 2s’2 2p’6

Question 15

Hybridization

Answer 15

Mixing different orbital types to form hybrid orbitals which have new shapes

Question 16

Sp3 hybridization

Answer 16

Combining s, px, py and pz orbitals to form 4 new ones that point towards the vertices of a tetrahedron to minimize repulsion
-has 25% s character and 75% p character
Carbon with 3 single (sigma) bonds

Question 17

Sp2 hybridization

Answer 17

One s orbital mixed with 2 p orbitals (33/67)
Seen in alkenes with double bonds the unhybridized p orbital is used to make the pi bond
Trigonal planar geometry
Carbon with one double bond

Question 18

Sp hybridized

Answer 18

When we have triple bonds we need 2 unhybridized p orbitals to make 2 pi bonds - or carbon may form 2 double bonds each with 1 pi bond
Linear structure - they are 180 apart
50/50 s/p character

Question 19

Delocalization of electrons in molecules that have conjugated bonds

Answer 19

Resonance

Question 20

Conjugation

Answer 20

When we have alternating double and single bonds we form a system of unhybridized p orbitals where pi electrons can relocalize in giving stability