Atomic and Nuclear Phenomena

Question 1

Photoelectric effect

Answer 1

The ejection of an electron from the surface of a metal in response to light

Question 2

Threshold frequency

Answer 2

The minimum light frequency necessary to eject an electron from a given metal

Question 3

Plancks Constant

Answer 3

h = 6.626x10-34 J•s

Question 4

Work function

Answer 4

The minimum energy necessary to eject an electron from a given metal

Question 5

Ejected electrons create __________

Answer 5

Current; the magnitude of this current is proportional to the intensity of the incident beam of light

Question 6

Bohr model of the atom

Answer 6

States: the electron energy levels are stable and discrete, corresponding to specific orbits

Question 7

Electron moving from low to high energy shells:

Answer 7

Absorb a photon of light of the same frequency as the energy difference between the orbits

Question 8

Electron moving from high to low energy shells:

Answer 8

Emits a photon of light of the same frequency as the energy difference between orbits

Question 9

Absorption Spectra

Answer 9

May be impacted by small changes in molecular structure

Question 10

Fluorescence

Answer 10

Occurs when a species absorbs high frequency light and then returns to its ground state in multiple steps. Each step has less energy than the absorbed light and is within the visible range of the electromagnetic spectrum

Question 11

Nuclear binding energy

Answer 11

The amount of energy that is released when nucleons (protons and neutrons) bind together

Question 12

4 Fundamental Forces of Nature

Answer 12

Strong nuclear force
Weak nuclear force
Gravitational force
Electrostatic force

Question 13

Mass defect

Answer 13

The difference between mass of the unbound nucleons and the mass of the bound nucleons within the nucleus

The amount of mass converted to energy during nuclear fusion

Question 14

Fusion

Answer 14

Occurs when small nuclei combine into larger nuclei

Question 15

Fission

Answer 15

Occurs when large nuclei split into smaller nuclei

Question 16

Radioactive decay

Answer 16

The loss of small particles from the nucleus

Alpha decay
Beta decay: positive and negative
Gamma decay
Electron capture

Question 17

Electron capture

Answer 17

The absorption of an electron from the inner she’ll that combines with a proton in the nucleus to form a neutron

**the reverse of beta decay

Question 18

Gamma decay

Answer 18

Gamma rays emitted: converting high energy nucleus into a more stable nucleus

NO CHARGE and NO CHANGES occur in the mass or atomic number

Question 19

Beta decay

Answer 19

Beta particle emission: an electron
Positive beta decay: proton is converted into a neutron
Negative beta decay: neutron is converted into a proton

Question 20

Negative beta decay

Answer 20

Creates negative beta particles; emitting: an electron and an antineutrino

Question 21

Positive beta decay

Answer 21

Creates positive beta particles; emitting a positron and a neutrino

Question 22

Positron emission

Answer 22

Induced decay: a positron is released

Question 23

Positron

Answer 23

Has the mass of an electron but has a positive charge

A neutrino is emitted in positron decay

Question 24

Alpha decay

Answer 24

The emission of an alpha particle: a Helium nucleus

Question 25

Half life

Answer 25

The amount of time required for half a sample of radioactive nuclei to decay

Question 26

Exponential decay

Answer 26

The rate which radioactive nuclei decay is proportional to the number of nuclei that remain