Chapter 38

Question 1

Rutherford proposed the “nuclear model” of the atom, which

Answer 1

posited a small positively charged nucleus surrounded by electrons.

Question 2

Bohr assumption:

Answer 2

he assumed that electrons can only orbit at certain discrete (i.e. quantized) distances from the nucleus:(𝑛=1, 𝑛=2, 𝑛=3, 𝑒𝑡𝑐.)

Question 3

Bohr assumption:

Answer 3

he assumed that electrons can only orbit at certain discrete (i.e. quantized) distances from the nucleus:(𝑛=1, 𝑛=2, 𝑛=3, 𝑒𝑡𝑐.)

Question 4

electric potential energy for electron in an atom

Answer 4

Question 5

Potential Energy: The work done by a conservative force

Answer 5

Question 6

The work done by a conservative force is defined as producing a change in

Answer 6

potential energy

Question 7

Electric potential energy

Answer 7

Question 8

Using the following definitions of work, show that an electron gains 1 𝑒𝑉 of potential energy when it moves across a 1 𝑉 capacitor

Answer 8

Question 9

Potential Energy (of an Electron)

Answer 9

Question 10

Electron Transitions

Answer 10

• When electrons transition from a higher orbit (higher energy state) to a lower orbit (lower energy state), a photon is emitted with energy 𝐸=ℎ𝑓.
• This energy is equal to the electron’s change in energy:
  𝐸_ℎ𝑖𝑔ℎ−𝐸_𝑙𝑜𝑤=𝐸_𝑝ℎ𝑜𝑡𝑜𝑛

Question 11

The Lyman series is due to

Answer 11

𝐾 𝑡𝑟𝑎𝑛𝑠𝑖𝑡𝑖𝑜𝑛𝑠

• The Balmer series is due to 𝐿 𝑡𝑟𝑎𝑛𝑠𝑖𝑡𝑖𝑜𝑛𝑠
• Note how the Δ𝐸 for the Balmer series are of the order of 1 𝑒𝑉. Remember that a photon of frequency in the visible light range has an energy of ≈1𝑒𝑉 (𝐸=ℎ𝑓)

Question 12

Spectrum of solar radiation

Answer 12

Question 13

Total energy of an electron on shell n:

Answer 13

Question 14

As an electron transitions between energy levels, from 𝑛_𝑖𝑛𝑖𝑡𝑖𝑎𝑙 to 𝑛_𝑓𝑖𝑛𝑎𝑙, energy is released as EM radiation.
From ni to nf, the energy released is:

Answer 14

Question 15

The expression for the wavelength of the emitted photon during an electron transition (in H)

Answer 15

where 𝑅 is the Rydberg constant