Atomic Structure and Nuclear Chemistry Review

Flashcards covering key vocabulary related to atomic theory, subatomic particles, atomic models, and nuclear chemistry based on lecture notes.

Democritus

Ancient Greek philosopher who stated that matter is made of ultimate, indivisible particles called 'atamos' (atoms).

Aristotle

Ancient Greek philosopher who stated that matter is continuous and has no ultimate particle, a view that was dominant until the 1700s.

Alchemists

Experimenters between 200 and 1700 AD who worked in secret, trying to turn base metals into gold, and discovered useful things like medicine and gunpowder.

Atomists (1600-1700 AD)

Scientists like Galileo, Boyle, Bacon, and Newton who openly stated and believed that matter is made of atoms, being the first since Democritus.

Antoine Lavoisier (1782)

Known as the 'Father of Modern Chemistry' for making quantitative observations about chemical reactions and proposing the Law of Conservation of Matter (Mass).

Law of Conservation of Matter (Mass)

States that in an ordinary chemical reaction, matter cannot be created or destroyed; it is only rearranged.

Joseph Proust (1799)

Famous for his studies of iron pyrite, which led to the formulation of the Law of Definite Proportions.

Law of Definite Proportions

States that elements that make up a compound are always in a certain proportion by mass.

John Dalton (1803)

English school teacher and chemist who proposed the first Atomic Theory after studying the works of Lavoisier and Proust.

Dalton's Atomic Theory (Key Postulates)

1) All matter is made up of atoms. 2) Atoms of the same element are the same. 3) Atoms of different elements are different. 4) In a chemical reaction, atoms are ONLY rearranged. 5) Atoms of different elements combine chemically in definite proportions to form compounds.

J.J. Berzelius (1811)

Established the modern system for element symbols.

Eugen Goldstein (1886)

Discovered Canal Rays (Anode Rays), which led to the development of mass spectrometry and eventually the discovery of protons.

Henri Becquerel (1896)

Discovered Radioactivity, which suggested that something was coming out of supposedly indivisible atoms.

J.J. Thomson (1897)

Discovered the Electron by studying Cathode Ray Tubes, determining electrons are negative particles, are the same from all atoms, and have a specific charge-to-mass ratio.

Plum Pudding Atom

J.J. Thomson's model of the atom, describing it as a sphere of positive matter in which electrons are embedded.

Proton

A subatomic particle that carries a +1 charge and has a mass of approximately 1 amu; discovered in Canal Rays by Wien.

Robert Millikan (1909)

Conducted the Oil Drop Experiment, which precisely determined the charge and mass of the electron.

Isotopes

Atoms of the same element that are chemically identical but have different masses due to a different number of neutrons.

Ernest Rutherford (1911)

Conducted the Gold Foil Experiment, which led to the conclusion that the atom is mostly empty space with a tiny, dense, positive core called the nucleus. 1/8000 came back looked through gold foil

Nuclear Atom

Rutherford's model of the atom, featuring a tiny, dense, positive nucleus surrounded by a large empty space containing electrons.

Niels Bohr (1913)

Proposed the Planetary Atom model, stating that electrons exist in allowed energy levels (orbits) that circle the nucleus like planets orbit the sun.

Bohr's Postulates

1) Electrons in an atom can only exist in energy levels if they have certain allowed energies. 2) Electrons with certain energy would orbit the nucleus at a distance determined by its energy.

Erwin Schrödinger (1926)

Developed the Electron Cloud (Quantum Mechanical) Atom model, which describes electrons as existing in mathematically defined regions called orbitals, rather than fixed orbits.

Orbital

A mathematically defined region in space around the nucleus where electrons are most likely to be found, according to the quantum mechanical model.

James Chadwick (1932)

Discovered the Neutron, a neutral subatomic particle, by bombarding a Beryllium atom with alpha particles.

Nucleus

The tiny, dense, central core of an atom, containing protons (charge +1, mass ~1 amu) and neutrons (charge 0, mass ~1 amu).

Electron Cloud

The mathematically defined region in space around the nucleus where electrons (charge -1, mass ~0 amu) with specific allowed energies are found.

Atomic Number (Z)

The number of protons in the nucleus of an atom, which identifies the element. In a neutral atom, it also equals the number of electrons.

Mass Number (A)

The sum of the number of protons and neutrons in the nucleus of an isotope, used to identify specific isotopes.

Atomic Mass (Atomic Weight)

The weighted average of the masses of all naturally occurring isotopes of an element, as listed on the periodic table.

Nuclear Radiation

Emission of particles or energy from an unstable atomic nucleus during radioactive decay, including alpha, beta, and gamma decay.

Fusion

A nuclear reaction where light atoms join to form a heavier atom, releasing a lot of energy, requiring high temperatures to start, and producing no radioactive waste.

Fission

A nuclear reaction where heavy atoms split into lighter atoms, releasing a lot of energy, requiring lower temperatures to start, and producing radioactive waste.

Alpha Decay

A type of radioactive decay that produces alpha particles (a helium-4 nucleus), which is the weakest form of radiation and can be stopped by paper, clothes, or skin.

Beta Decay

A type of radioactive decay that produces beta particles (an electron), which can be stopped by glass, wood, or thin sheets of metal.

Gamma Decay

A type of radioactive decay that produces gamma rays (high-energy electromagnetic radiation), which have no charge or mass, and are the strongest form of radiation, requiring thick sheets of lead or concrete to stop.

Atomic mass formula

Mass of isotope X % of abundance/100

Mass number vs atomic mass

the mass number is a count of the particles in a single atom's nucleus, while the atomic mass is the weighted average of the masses of all the naturally occurring isotopes of an element. 

Avogrado’s number

This is the number of representative particles (e.g., atoms, molecules, or ions) in one mole of any substance. 

Molar mass

the mass of one mole of a substance, expressed in grams per mole (g/mol)

Crooks tubes

led to the discovery of the electron and the understanding of subatomic particles.