Week 12

Question 1

Heisenberg uncertainty principle

Answer 1

We cannot simultaneously know the location and energy of an electron

Question 2

Trident symbol

Answer 2

Trident symbol = mathematical function relating location of an electron to the amplitude of its wave, which corresponds to its energy
- each wave function is associated with a particular energy
- can only consider probabilities if finding and electron

Question 3

Wave functions

Answer 3

Also known as orbitals
Quantum numbers are used to characterise them

Question 4

Orbital

Answer 4

A region of the atom where an electron is most likely to reside
Probability is given by solution of the Schrödinger equation

Question 5

Principle quantum number

Answer 5

Must be a positive integer
Energy levels labelled n
Defines the general size and energy of an energy level
Also known as the shell number
Electrons that belong to a specific shell are most likely to be found in that sphere
As n increases, energy increases
- positively charged by Lewis stabilise negatively charged electrons
- electrostatic interaction

Question 6

Angular momentum quantum number

Answer 6

Shape of an orbital is defined by the angular momentum quantum number, L
Integer values only, can have values
L= 0,1,2 …… n-1
Orbitals with the same value of L form a sub shell

Question 7

Orbital shapes

Answer 7

L=0 are known as s-orbitals
L=1 are p orbitals

Shapes represent the 3D regions of space within which the electron is likely to be found

Question 8

Radial nodes

Answer 8

A radial node is the radius in which a certain distance from the nucleus means the probability of finding an electron is zero
The number of radial nodes in an orbital is n-L-1

Question 9

Angular node

Answer 9

A region where the angular wave function of an electron in Ana Tom is zero

Question 10

Orbital energies

Answer 10

Energy increases with n
Energy increases slightly with L
Orbitals with the same n and L have the same energy

Question 11

Spun quantum number

Answer 11

Specifies the spin of an electron, ms

1/2 or -1/2

Question 12

Pauli extension principle

Answer 12

Allows us to understand how electrons occupy orbitals
No two electrons in the same atom can have exactly the same quantum numbers
Electrons can share the same orbital provided the spin is different

Question 13

Electron configurations

Answer 13

Energy of atomic orbitals increases as n increases - size of orbital increases with n
Repulsion between electrons makes energies sub shells differ with increasing l
Can cause overlaps

Question 14

Shielding

Answer 14

As n increases, less electron density is found close to the nucleus
Electrons close to the nucleus slightly repel those that are further out, which offsets the attraction between nucleus and electron
In large orbitals relative energies become more difficult to predict