Magnetochemistry Introduction

Question 1

What does magnetism arise from ?

Answer 1

From the electrons in a material and the orbitals they occupy.

Question 2

What is the relationship between the magnetic force exerted between two poles (p1 and p2) and the distance between them (r)?

Answer 2

Question 3

What are the two contributions to the magnetic moment of an atom?

Answer 3

The orbital motion of electrons around the nucleus AND the spin of the electrons

Question 4

What is the principal quantum number (n)

Answer 4

The energy of an electron in atom. Defines which shell the electron is located in.

Question 5

What is the orbital angular momentum quantum number (l)

Answer 5

Tells us which subshell the election is in.

Question 6

What is the magnetic quantum number (ml)

Answer 6

Tells us the allowed orientations of the orbital angular momentum in an applied magnetic field. Also tells us how many orbitals are in a subshell.

Question 7

When n=2 what are the allowed values of l and ml?

Answer 7

2 allowed values of l(l=0 and l=1)
These l values describe the S and P orbitals respectively. For the S orbital ml=0 and for the P orbital ml=(2(1)+1)=3

Question 8

How do you determine the magnitude of the orbital angular momentum of an electron?

Answer 8

Question 9

How do you find the orbital magnetic moment of an electron given the orbital angular momentum?

Answer 9

Question 10

How are the orbital angular momentum and the magnetic moment related?

Answer 10

Question 11

How are the orbital angular momentum and the magnetic moment related?

Answer 11

Question 12

How do you work out the magnitude of the magnetic moment ?

Answer 12

MB is a unit(Bohr Magnetons)

Question 13

How do you work out the component of the magnetic moment polarised along a magnetic field?

Answer 13

Question 14

What unit is used to describe all atomic magnetic moments?

Answer 14

Böhr Magnetons
(Amperes per metre squared in SI units)

Question 15

What happens to an electrons spin angular momentum when a magnetic field is applied?

Answer 15

It is split into 2s+1 levels described by the spin magnetic quantum number (s)

Question 16

How do you determine the magnitude of the spin angular momentum of an electron?

Answer 16

Question 17

What is the component of the spin angular momentum along an applied magnetic field?

Answer 17

Question 18

Given the spin angular momentum of an electron, how do you determine the magnetic moment that is proportional to it?

Answer 18

Question 19

How do you determine the magnitude of the magnetic moment associated with the spin angular momentum? ‘

Answer 19

Question 20

How do you determine the component of the spin magnetic moment polarised along a magnetic field?

Answer 20

Question 21

What do the orbital (L) and spin (S) angular momenta couple to give?

Answer 21

The total angular momentum, J

Question 22

How do you determine the magnetisation of a material (total magnetic moment per unit volume)?

Answer 22

Question 23

When a magnetic field (H), is applied to a material with a magnetisation (M), how is the magnetic induction (B) determined

Answer 23

Question 24

How do you calculate the magnetic susceptibility?

Answer 24

Question 25

What are the characteristics of diamagnetic susceptibilities?

Answer 25

Small magnitude, negative and temperature independent.
It arises in materials that have no unpaired electrons, meaning their electron shells are full and have no net orbital or spin angular momentum.
Applying a magnetic field causes a change in the orbital motion of the electrons so we still see an overall magnetic response.
The negative susceptibility means that applying a magnetic field induces a magnetisation that opposes the magnetic field.

Question 26

What are the characteristics of paramagnetic susceptibilities?

Answer 26

Positive and temperature dependant.