Chem Test 2

Question 1

Problems with the Bohr Model?

Answer 1

1. Doesn’t explain why the angular momentum and energy of electron is quantized,
2. could not be extended to other atoms
3. doesn’t explain why H atom emits radiation continuously?

Question 2

New physical laws to describe the benhaviour of electrons in atoms? (after the H Bohr model)

Answer 2

1. de Broglie’s hypothesis - particles exhibit a wave-particle duality
2. Heisenberg uncertainty principle - we can never know the true behaviour of a system

Question 3

Evidence of wave-particle duality?

Answer 3

• diffraction suggests light behaves as a wave.
  constructive: ring
  destrcutive: node
• the photoelectric effect suggests light behaves as particles

Question 4

Heisenberg uncertainty principle?

Answer 4

If we tried to measure the position of an electron, we will change its momentum (motion of mass)

Question 5

n quantum number

Answer 5

the size of an orbital
Any integer

Question 6

l quantum number

Answer 6

orbital angular momentum quantum number (shape of orbital)
restricted to n-1

Question 7

ml quantum number

Answer 7

magnetic quantum number (number of distinct orientations allowed for particular orbital)
restricted to -l to +l

Question 8

Probability density plots

Question 9

Blackbody radiation experiement

Answer 9

Atoms in a heated solid oscillate with certain energies only

Question 10

Photoelectric effect

Answer 10

The energy of light is highly localized and is proportional to its frequency

Question 11

Line spectra of atoms

Answer 11

The energy of an electron in an atom is not arbitrary, but rather it is restricted to have certain “special” values

Question 12

Penetration

Answer 12

a measure of how close a particular electron gets to the nucleus

Question 13

Shielding

Answer 13

indicates how thoroughly a particular electron is blocked from the nucleus

electrons with lower values for n prevent electrons with higher values of n from feeling the nuclear charge

Question 14

Pauli Exclusion Principle

Answer 14

no two electrons in the same atom can have identical values for all four of their quantum numbers -
must have opposite spins

Question 15

The Aufbau Procedure

Answer 15

electrons fill lower-energy atomic orbitals before filling higher-energy ones

Question 16

Hund’s Rule

Answer 16

requires single occupancy before pairing of an orbital