Atomic and Nuclear Phenomena Flashcards
Photoelectric effect
The ejection of an electron from the surface of a metal in response to light
Threshold frequency
The minimum light frequency necessary to eject an electron from a given metal
Plancks Constant
h = 6.626x10-34 J•s
Work function
The minimum energy necessary to eject an electron from a given metal
Ejected electrons create __________
Current; the magnitude of this current is proportional to the intensity of the incident beam of light
Bohr model of the atom
States: the electron energy levels are stable and discrete, corresponding to specific orbits
Electron moving from low to high energy shells:
Absorb a photon of light of the same frequency as the energy difference between the orbits
Electron moving from high to low energy shells:
Emits a photon of light of the same frequency as the energy difference between orbits
Absorption Spectra
May be impacted by small changes in molecular structure
Fluorescence
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
Nuclear binding energy
The amount of energy that is released when nucleons (protons and neutrons) bind together
4 Fundamental Forces of Nature
Strong nuclear force
Weak nuclear force
Gravitational force
Electrostatic force
Mass defect
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
Fusion
Occurs when small nuclei combine into larger nuclei
Fission
Occurs when large nuclei split into smaller nuclei
Radioactive decay
The loss of small particles from the nucleus
Alpha decay
Beta decay: positive and negative
Gamma decay
Electron capture
Electron capture
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
Gamma decay
Gamma rays emitted: converting high energy nucleus into a more stable nucleus
NO CHARGE and NO CHANGES occur in the mass or atomic number
Beta decay
Beta particle emission: an electron
Positive beta decay: proton is converted into a neutron
Negative beta decay: neutron is converted into a proton
Negative beta decay
Creates negative beta particles; emitting: an electron and an antineutrino
Positive beta decay
Creates positive beta particles; emitting a positron and a neutrino
Positron emission
Induced decay: a positron is released
Positron
Has the mass of an electron but has a positive charge
A neutrino is emitted in positron decay
Alpha decay
The emission of an alpha particle: a Helium nucleus
