Atomic & Quantum Phenomena

Question 1

Gold Foil Experiment

Answer 1

Experiment that determined an atom is mostly empty space with a tiny region called the nucleus that has a positive charge. Electrons orbit the nucleus

Question 2

Planck’s Constant

Answer 2

h = 6.63 * 10^-23 J/s
h = 4.14 * 10^-15 Electron Volts/s

Question 3

Energy of a photon

Answer 3

E = hf
E = hc/λ

Question 4

Absorption

Answer 4

Upward arrow on energy level diagram,

Electron final = Electron initial + Ephoton

Question 5

Emission

Answer 5

When light given off by atom when electrons drop to lower energy levels
Ephoton = Einit - Efinal
*note Efinal and Einit are negative

Question 6

Ionization Energy

Answer 6

Minimum energy for an electron to leave the atom

Question 7

Work function and Max Kinetic Energy equations

Answer 7

Φ = abs(E ground state)
Kmax = Ephoton - Φ
UE = Kmax

Question 8

Photoelectric effect

Answer 8

Electrons are ejected from metallic substances when radiated with high-energy photons.
Electrons move from Cathode to Anode, creating Potential Electric Energy = Kmax.
Provides evidence that light has a particle characteristic rather than a wave

Question 9

Photoelectric effect experiment

Answer 9

Photocell, ammeter, variable power supply. Create electrical energy pointing towards each other, when ammeter reads 0, V power supply = V photocell

Question 10

Key observations of the Photoelectric effect experiment

Answer 10

1. Photons with low frequencies created no potential in photocell, so no electrons were ejected (hf - Φ = Kmax)
2. As frequency increased, threshold frequency was encountered such that electrons began ejecting
3. Increase in frequency also increased the energy of emitted electrons

Question 11

When frequency is constant in the Photoelectric effect experiment

Answer 11

1. Increasing the intensity of the light increases the number of photons incident on the photocell, more electrons ejected
2. But the intensity has no effect on the voltage of the photocell or energy
3. If the power supply is adjusted to 0, voltage of the photocell creates a current flow. Increasing the intensity of light increases the current flowing through the circuit.