Physical and Inorganic Chemistry

Question 1

What is the photoelectric effect?

Answer 1

When ultraviolet with wavelengths from 2000 - 4000 A incident upon a metallic surface and electrons are emitted with some velocity.

Question 2

What is the energy of the ejected photoelectron dependent on?

Answer 2

Dependent on the frequency of the incident radiation not upon it’s intensity.

Question 3

What does higher intensity monochromatic light produce?

Answer 3

More photoelectrons all with the same energy.

Question 4

What were the results of Rutherford and Gieger’s studies?

Answer 4

1. The majority of alpha particles penetrate the gold foil undetected
2. A few particles were scattered through a small angle
3. A few suffered serious deflections as they passed through
4. A few underwent direct backward scattering along the original pathway

Question 5

What did Niels Bohr demonstrate?

Answer 5

Electrons are restricted to a specific set of energy levels - the energies are quantised.

Question 6

What does wave-particle duality mean?

Answer 6

Electrons can behave as waves or particles but not at the same time.

Question 7

What is the Heisenberg Uncertainty Principle?

Answer 7

“The more precisely the position is determined the less precisely the momentum is known.”

Question 8

What does an electrons associated wavefunction describe?

Answer 8

The electron wave

Question 9

How is the form of the wavefunction determined?

Answer 9

Using the Schrodinger equation.

Question 10

What allows us to determine atomic orbitals?

Answer 10

Approximate solutions to the Schrodinger equation.

Question 11

What do atomic orbitals tell us?

Answer 11

The probability of finding an electron at a particular point in an atom.

Question 12

What does the principal quantum number, n, correspond to?

Answer 12

The gross orbital energy/ shell energy.

Question 13

What does the orbital quantum number, l, correspond to?

Answer 13

The shape of the orbital (n-1).

Question 14

What does the magnetic quantum number, ml, correspond to?

Answer 14

The orientation of the orbital. (-l through 0 to +l).

Question 15

What are degenerate orbitals?

Answer 15

Those with the same energy.

Question 16

What does the Aufbau Principle tell?

Answer 16

1. Lowest energy orbitals fills first
2. When filling degenerate orbitals no pairing occurs until each orbital contains one electron.
3. Only two electrons can occupy an orbital

Question 17

What are the valence electrons

?

Answer 17

Electrons in the shell with the highest value of n.

Question 18

What does Lewis Structure show?

Answer 18

The nature of bonding in a molecule or ion.

Question 19

What does VSEPR theory explain?

Answer 19

The vast majority of molecular geometries.

Question 20

How are valence shell electron pairs arranged?

Answer 20

To minimise repulsions between themselves.

Question 21

What is basic geometry controlled by?

Answer 21

The number of sigma bonding electron pairs.

Question 22

What does the Born-Oppenheimer approximation suppose?

Answer 22

Nuclei move relatively slowly due to weight and so can be treated as being fixed at arbitrary locations.

Question 23

How are bonding orbitals formed?

Answer 23

When atomic orbitals interfere constructively.

Question 24

How are anti bonding orbitals formed?

Answer 24

when atomic orbitals interfere destructively.

Question 25

What can be determined by the potential energy curve?

Answer 25

the equilibrium bond length.

Question 26

What are the four stabilising interactions?

Answer 26

• Electron 1 and nucleus A
• Electron 2 and nucleus B
• Electron 1 and nucleus B
• Electron 2 and nucleus A

Question 27

What are the two destabilising interactions?

Answer 27

• Electron 1 and electron 2

- Nucleus A and nucleus B

Question 28

How is a chemical bond thought of in valence bond theory?

Answer 28

As being localised between 2 atoms.

Question 29

What is combined to give hybrid orbitals?

Answer 29

Pure atomic orbitals.

Question 30

When is a bond formed in valence bond theory?

Answer 30

When hybrid orbitals of different atoms overlap.

Question 31

What is electron promotion?

Answer 31

Moving an electron into a higher energy level.

Question 32

How are molecular orbitals formed in molecular orbital theory?

Answer 32

Pure atomic orbitals on different atoms are combined.

Question 33

What is bond order?

Answer 33

A guide to the kind of bond between atoms.

Question 34

What is the bond order formula?

Answer 34

(bonding - antibonding) /2

Question 35

Which orbital fills first in neutral atoms - 4s or 3d?

Answer 35

4s as it is lower energy.

Question 36

Why are 4s orbitals removed in +2 transition metal ions?

Answer 36

To increase stability

Question 37

Why does the removal of electrons from the s-orbital result in a more stable +2 ion?

Answer 37

As the s-electrons are able to shield the 3d electrons very well so when they are removed the d-electrons feel a much greater effective nuclear charge.

Question 38

Why is there a greater repulsion between electrons across the period?

Answer 38

There is an increase in the number of d-electrons.

Question 39

What makes transition metals useful catalysts (metalloenzymes)?

Answer 39

Their ability to exist in variable oxidation states

Question 40

What carries oxygen in the blood stream in mammals?

Answer 40

Haemoglobin

Question 41

What stores oxygen in mammalian tissue?

Answer 41

Myoglobin

Question 42

What are haemocyanins?

Answer 42

Oxygen carrying copper - containing proteins in molluscs and arthropods.