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Vocabulary flashcards covering cosmology, nucleosynthesis, early atomic theory, and chemical bonding concepts from the lecture notes.
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Big Bang Model
Explanation of the simultaneous appearance of space everywhere followed by expansion and cooling, not a theory but a cosmological model.
Primordial Nucleosynthesis
Early-universe process that formed the light elements hydrogen, helium, lithium, and beryllium within the first few minutes after the Big Bang.
Stellar Nucleosynthesis
Fusion processes inside stars that build elements from boron up to iron.
Supernova Nucleosynthesis
Creation of elements heavier than iron (e.g., gold) during explosive deaths of massive stars.
Hubble’s Law
Observation that galaxies recede from Earth at speeds proportional to their distance, implying an expanding universe.
Edwin Hubble
Astronomer who, with Milton Humason, discovered that nebulae are distant galaxies and formulated Hubble’s Law.
George Gamow
Physicist who proposed that a hot, dense early universe produced light elements through nucleosynthesis.
Ralph Alpher
Co-author of the α–β–γ paper supporting Gamow’s Big Bang nucleosynthesis predictions.
Hans Bethe
Scientist who explained that nuclear reactions in stars create heavier elements.
Deuterium
Isotope of hydrogen containing one proton and one neutron; formed during Big Bang nucleosynthesis.
Silicon Burning
Late stellar fusion phase that produces iron, the heaviest element formed in stellar cores.
Beta Decay
Radioactive process where a neutron converts to a proton with emission of an electron, creating a nucleus of the next higher atomic number.
Neutron Capture
Addition of a neutron to a nucleus, potentially forming a heavier isotope or element.
s-Process (Slow Neutron Capture)
Neutron captures separated by thousands of years inside a star’s carbon core, producing nuclei up to lead (Z = 82).
r-Process (Rapid Neutron Capture)
Burst of neutron captures during a supernova that creates very heavy, neutron-rich nuclei like uranium and plutonium.
Thales of Miletus
Early Greek thinker who proposed that water is the fundamental substance from which matter arises.
Leucippus and Democritus
Greek philosophers who originated atomism, asserting that matter is composed of indivisible atoms moving in the void.
Aristotle (Four Qualities)
Philosopher who rejected atomism, defining matter by hot, cold, wet, and dry qualities combining into earth, air, fire, and water.
Alchemists
Medieval experimenters who developed laboratory apparatus, acids, salts, and symbolic notation while attempting to transmute metals into gold.
Paracelsus
Renaissance physician-alchemist who coined the term “alcohol” and advanced medical chemistry.
Atomic Number (Z)
Number of protons in an atom’s nucleus; identifies the element.
Atomic Mass (A)
Total number of protons and neutrons in an atom’s nucleus.
Isotope
Atoms of the same element with different numbers of neutrons, hence different masses but identical atomic numbers.
Polarity (Molecular)
Uneven distribution of electrical charge in a molecule determined by electronegativity differences and molecular geometry.
Electronegativity
Ability of an atom to attract electrons in a chemical bond; increases toward the upper right of the periodic table.
Non-Polar Covalent Bond
Bond with an electronegativity difference < 0.4; electrons are shared equally.
Polar Covalent Bond
Bond with a moderate electronegativity difference (0.4 < ΔEN < 1.8); electrons shared unequally.
Ionic Bond
Bond with an electronegativity difference > 1.8; electron transfer creates ions.
Symmetrical Molecule
Molecular shape with balanced charge distribution, resulting in overall non-polarity.
Asymmetrical Molecule
Shape in which charge distribution is uneven, making the molecule polar.
VSEPR Theory
Valence-shell electron-pair repulsion model stating that electron pairs arrange to minimize repulsion, determining molecular geometry.
Intermolecular Forces (IMF)
Attractive forces between molecules influencing boiling point, melting point, viscosity, and surface tension.
London Dispersion Force
Weakest IMF arising from temporary electron fluctuations; present in solids, liquids, and gases.
Dipole–Dipole Force
Attraction between permanent dipoles of polar molecules.
Hydrogen Bond
Strong dipole–dipole interaction between hydrogen and highly electronegative atoms (F, O, or N).
Ion–Dipole Interaction
Attractive force between an ion and the oppositely charged pole of a polar molecule.
Surface Tension
Measure of a liquid’s surface resistance; increases with stronger intermolecular forces.
Viscosity
Resistance to flow in a liquid, heightened by stronger intermolecular attractions.
Element Lead (Pb) Limit
Upper atomic number (82) reachable via the s-process in stellar interiors.
Rapid Supernova Environment
Extremely dense, neutron-rich setting where the r-process produces the heaviest elements.