Introduction to Atomic Theory and Subatomic Structure

Flashcards covering chemical laws, early atomic theories, key historical experiments, and fundamental subatomic particles from lecture notes.

Law of Definite Proportion

A chemical law stating that all samples of a given compound have the exact same composition and proportion by mass of constituent elements (for example, water is always $88.8\text{\%}$ oxygen and $11.2\text{\%}$ hydrogen).

Joseph Clue

The researcher who developed the law of definite proportion in 1799.

Law of Multiple Proportions

A law stating that when two or more compounds are formed from the same elements using a fixed mass of one element, the masses of the second element exist in small whole-number ratios (such as $2:1$).

John Dalton

The chemist who published the very first atomic theory based on previously observed laws.

Indivisible Atom

The fundamental concept in Dalton's atomic theory asserting that elements consist of tiny, unbreakable particles that serve as the fundamental unit of matter.

Dalton's Atomic Theory

A theory postulating that elements consist of tiny indivisible atoms, atoms of a given element are identical, compounds form from combinations of different atoms in fixed relative ratios, and chemical reactions involve atom reorganization without creating or destroying atoms.

JJ Thomson

The scientist who studied cathode ray tubes and discovered that atoms emit tiny, negatively charged subatomic particles called electrons.

Cathode Rays

Beams of negatively charged electrons emitted from the surface of metal inside cathode ray tubes.

Robert Milliken

The scientist who conducted oil droplet experiments inside a magnetic field to determine the actual charge and mass of an electron.

Billy Helms' Linskin

The scientist credited with taking the first X-ray ever of a human hand (his wife's hand with a wedding ring).

Murray Curie

The scientist who named radioactivity, describing energy emissions as well as negatively and positively charged particle emissions from atoms.

Radioactivity

Energy emissions or charged particle emissions (positive or negative) coming from atoms, named by Murray Curie.

Rutherford's Gold Foil Experiment

An experiment conducted by Rutherford, Beiger, and Martin where radioactivity shot at thin gold foil revealed that an atom's positive charge is concentrated in a tiny spot in the center.

Beiger and Martin

The postdoc (Beiger) and undergraduate student (Martin) who worked with Rutherford on the gold foil experiment.

James Chad

The scientist credited with discovering the neutron as a massive nuclear particle with no charge 20 to 30 years after Rutherford's nuclear discovery.

Billiard Ball Model

An early atomic model describing the atom as a sphere of mass that cannot be broken apart but can collide with other spheres.

Plum Pudding Model

Thomson's model depicting the atom as a sphere of dispersed positive charge with negative electrons distributed across its surface.

Proton

A subatomic particle located inside the nucleus with a relative mass of $1$ and a relative charge of $+1$ ($+1.602 \times 10^{-19}\text{\text{ coulombs}}$).

Electron

A subatomic particle located outside the nucleus with a relative mass of effectively $0$ (less than $2000$ times lighter than a proton) and a relative charge of $-1$ ($-1.602 \times 10^{-19}\text{\text{ coulombs}}$).

Neutron

A neutral subatomic particle located inside the nucleus with a relative mass of $1$ and zero charge.