1.3 Atomic Structure and 1.4 Average Atomic Mass

Vocabulary flashcards covering atomic theory, subatomic particles, radioactivity, and atomic mass calculations based on lecture notes.

Dalton's Atomic Theory

A theory stating that each element is made up of identical atoms, different elements are fundamentally different, chemical compounds form when atoms of different elements combine, and chemical reactions involve the reorganization of unchanged atoms.

Cathode Ray Tube

A sealed glass vacuum tube that converts electrical signals into visible images by using an electron gun to shoot a beam of electrons across a vacuum at a glowing phosphor screen.

Robert Millikan

Scientist who discovered the charge of an electron, measured as $1.6 \times 10^{-19}\text{ C}$.

Radiation

The emission and transmission of energy through space in the form of waves.

Radioactivity

The spontaneous emission of particles and/or radiation, discovered by Antoine Becquerel via uranium.

Marie & Pierre Curie

Scientists who worked on radium and polonium.

Alpha radiation

Radiation consisting of positively charged particles.

Beta radiation

Radiation consisting of negatively charged particles.

Gamma radiation

Neutral high-energy radiation similar to an x-ray.

X-ray

Highly energetic radiation discovered by Wilhelm Röntgen that penetrates matter and darkens photographic plates, carrying no charge and not deflected by a magnet.

Ernest Rutherford

Scientist who conducted the thin gold foil experiment by firing positive alpha particles at gold foil, proving atoms are mostly empty space with a tiny, dense, positive nucleus.

Eugene Gold Stein

Scientist associated with the proton, defined as a positive subatomic particle.

Atomic number

The number of protons in the nucleus of an atom, which equals the number of electrons in a neutral atom, associated with H.G.J. Mosiey.

James Chadwick

Scientist who discovered the neutron, a subatomic particle with a mass of $1.67493 \times 10^{-24}\text{ g}$.

Isotopes

Atoms of the same element that differ in their number of neutrons and mass numbers.

Average atomic mass

A value computed from the atomic masses of stable isotopes.

Atomic mass unit (amu)

A unit of mass where $1\text{ amu} = 1.66 \times 10^{-24}\text{ g}$ and $1\text{ g} = 6.02 \times 10^{23}\text{ amu}$.