Exam 1 Atomic Structure and Nuclear Physics

These flashcards cover key concepts related to atomic structure and nuclear physics, providing definitions and explanations to assist in exam preparation.

Nuclide

An atom with a specific number of protons and neutrons, can be stable or unstable.

Element

Defined by the number of protons in its atomic nucleus.

Atomic size

An atom is about 10^-10 m or 0.1 nm in diameter.

Ionization ease of metals vs noble gases

Li, Na, K are easier to ionize than He, Ne, Ar due to fewer protons holding outer electrons.

Electron mass (kg)

9.11×10^-31 kg.

Proton mass (kg)

1.67×10^-27 kg.

Neutron mass (kg)

1.675×10^-27 kg.

Kinetic energy and mechanics at 10,000 m/s

Relativistic mechanics are more appropriate.

Ionization energy range for elements

1-25 eV depending on the element.

Atomic weight

The weighted average of isotopes in nature.

Photoelectric effect

A photon is absorbed, leading to the ejection of an electron.

Compton scattering

A photon collides with an electron, losing energy and changing direction.

Particle-wave duality

Particles exhibit both wave-like and particle-like behavior.

X-rays source

Produced from electron transitions, not nuclear processes.

Orbital electrons in radioactive decay

Usually not involved, but exceptions include electron capture and internal conversion.

Kinetic energy conservation

Not conserved in ionization, but total energy is conserved in radioactive decay.

Elastic reaction

Kinetic energy is conserved.

Mass defect

The mass of an atom is smaller than the sum of the masses of its elementary particles.

Quantum mechanics and atom stability

Electrons occupy quantized orbitals preventing collapse into the nucleus.

Excited atom radiation

Quantized energy levels lead to emission at discrete wavelengths.

Four fundamental forces

Gravitational, electromagnetic, strong nuclear, and weak nuclear forces.

Charge of ionized atom

Becomes positive if an electron is lost, negative if gained.

Speed of light invariance

The measured speed of light is the same for all observers.

Relativistic mass

Increases as the speed of an object increases.

Length contraction

Length decreases along the direction of motion as speed increases.

Time dilation

Moving clocks tick slower according to observers.

Mass-energy equivalence

Mass can be converted to energy and vice versa through E=mc².

Heisenberg Uncertainty Principle

States that precise position and momentum of particles cannot be known simultaneously.

Energy in chemical vs nuclear reactions

Chemical reactions relate energy in eV, while nuclear reactions relate in MeV.

Atomic models

Different models of the atom include Dalton's, Thomson's, Rutherford's, Bohr's, and Quantum Mechanical.

Neutron-to-proton ratio

Increases with atomic number to maintain nuclear stability.

Role of neutrons in nucleus stability

They bind nucleons without adding charge repulsion.

Nuclear stability relationship

Higher binding energy means more stability; odd-even pairs are less stable.

Q value in exothermic reactions

Positive indicating mass defect and energy release.

Excited state nucleus mass

Larger due to extra energy according to E=mc².

Alpha particle kinetic energy relation to Q value

Maximum kinetic energy relates to the Q value and recoil mass.

Beta particle kinetic energy variation

Energy varies due to shared energy with neutrinos.

Definition of nuclear stability

Resistance to radioactive decay, higher binding energy per nucleon indicates more stability.

Fusion advantages over fission

More energy per mass of fuel, abundant fuel, and no long-lived radioactive waste.

Reaction thresholds

Energy threshold must be exceeded for reactions; Coulomb barrier must be overcome for charged particles.

De Broglie wavelength relationship

Wavelength decreases as kinetic energy or momentum increases.