Chapter 2: Electronic Structure Of The Atom

Question 1

How is the periodic table arranged?

Answer 1

Based on similarities in chemical behaviour and atomic weight.

Question 2

Bohr’s Theory

Answer 2

• Electrons orbit the nucleus in fixed energy levels known as principle quantum number (n).
• Orbits further from the nucleus exist at higher energy levels.
  -When electrons return to a lower energy level, they emit energy in the form of light.

Question 3

What does Schrödinger wave equation describe?

Answer 3

The properties of electrons in atoms via position, mass, total energy, and potential energy.

Question 4

What is the particle-wave duality?

Answer 4

Established by De Broglie states quantum entities exhibit particle or wave properties according to the experimental circumstances.

Question 5

De Broglie equation

Answer 5

λ = h/vm

λ: wavelength
h: Planck’s constant
v: velocity
m: mass

Question 6

What is the solution of Schrödinger wave equation?

Answer 6

The wave function

Question 7

Define wave function?

Answer 7

Mathematical function describing the behaviour of an electron it consists of a radial and angular component.

Question 8

What is atomic orbital?

Answer 8

The region of space define by wave function.

Question 9

Results of Schrödinger wave equation

Answer 9

• Behaviour of electrons in regions of space called orbitals, through solution of equation; wave function
• Find energy values associated with particular wave function.
• Quantization of energy levels

Question 10

What 4 quantum number characterise atomic orbitals?

Answer 10

• Principle Quantum Number (n)
• Orbital Quantum Number (l)
• Magnetic Quantum Number (ml - l subscript)
• Spin Quantum Number (ms- s subscript)

Question 11

Principle Quantum Number

Answer 11

Responsible for determining the overall energy of the atomic orbital.
- Positive integers (1,2,3)

Question 12

Orbital Quantum Number

Answer 12

Determined the angular component and the shape of an orbital.
- 0, 1, 2, n-1

Question 13

Magnetic Quantum Number

Answer 13

Determined the orientation of an orbital.
- -l ….. +l

Question 14

Spin Quantum Number

Answer 14

Describes spins of the electrons in a given orbital.
- +/- 1/2

Question 15

What does different “l” values represent?

Answer 15

Different shapes of orbitals; eg s, p, d, f

Question 16

Define node

Answer 16

The point where the electron probability is zero.

Question 17

Define Degenerate Orbitals

Answer 17

Orbitals that possess the same energy.

Question 18

What is the angular component of orbitals associated with?

Answer 18

It is associated with geometry and orientation of the orbitals, and it changes its sign in nodal planes.

Question 19

s Orbitals

Answer 19

l = 0, ml = 0 (singly degenerate, only 1 s atomic orbital)

Question 20

p Orbital

Answer 20

l = 1, ml = -1, 0, +1 (triply degenerate, 3 p atomic orbitals)

Question 21

d Orbital

Answer 21

l = 2, ml = -2, -1, 0, +1, +2 (five-fold degenerate, 5 d atomic orbitals)

Question 22

f Orbital

Answer 22

l = 3, ml= -3, -2, -1, 0, +1, +2, +3 (seven-fold degenerate, 7 f atomic orbitals)

Question 23

What is the radial component of orbitals associated with?

Answer 23

Radial component of a wave function is associated with size of the orbitals.
- Decays exponentially with distance from nucleus (increase in r).
- Changes in sings in nodes

Question 24

Radial Distribution Function

Answer 24

4πr^2R(r)^2

Question 25

What does the Radial Distribution Function determine?

Answer 25

Describes the probability of finding an electron at a given distance from the nucleus.

Question 26

Define a node

Answer 26

A surface where the wave function is zero as it changes sign. Probability of finding electrons is zero.

Question 27

Which orbital have no radial nodes?

Answer 27

The lowest energy orbital of each classification (1s, 2p, 3d & 4f) has not radial node.

Question 28

Where is the p orbital’s nodal plane?

Answer 28

Through the nucleus

Question 29

Aufbau principle

Answer 29

• Electrons are placed in the lowest energy orbitals first.
• Covers the continual addition of electrons with increasing quantum numbers.

Question 30

Pauli Exclusion Principle

Answer 30

Requires each electron in an atom to have a unique set of quantum numbers.

Question 31

Hund’s Rule Of Maximum Multiplicity

Answer 31

Requires electrons be placed in orbitals to give the maximum total spin possible.
Electrons will occupy degenerate energy levels singly first before pairing up.

Question 32

Why does Hund’s rule work like it does?

Answer 32

2e- in the same orbital have higher energy then 2e- in different orbitals (spin-paring energy; electrostatic replusion).

Question 33

How does electron shielding work?

Answer 33

Inner shell e- shield from the attractive forced of nucleus with outer shell e- .

Question 34

Slates Rule