Atomic Theory and Models Flashcards

Vocabulary flashcards covering early atomic theories, including Greek atomic concepts, Mendeleev's periodic table, Dalton's atomic theory, and Thomson's plum pudding model.

Atom

The smallest particle of an element that cannot be divided or broken by chemical means, serving as the fundamental building blocks of matter that is electrically neutral and essentially empty space.

Atomos

A Greek word meaning indivisible or not to be cut, from which the name atom is derived.

Dmitri Mendeleev

A Russian scholar who showed that arranging elements in order of increasing atomic mass resulted in a periodic repetition of similar chemical properties, leading to the first periodic table of the elements.

Four Substances (Greek's Atom)

The four substances—Earth, Water, Air, and Fire—that composed all matter according to Greek atomic theory.

Four Basic Essences

The four modifying essences—wet, dry, hot, and cold—that modified the four basic substances in various proportions in Greek atomic theory.

John Dalton

An English schoolteacher who proposed in 1808 that an element was composed of identical atoms that reacted the same way chemically.

Hooks and Eyes

Features in John Dalton's atomic model used to account for chemical combination, where the size and number differed for each element.

J.J. Thomson

A researcher who in the late 1890s investigated the physical properties of cathode rays (electrons) and concluded that electrons were an integral part of all atoms.

Plum Pudding Model

J.J. Thomson's atomic model in which negative electric charges (electrons) were represented as plums within a pudding consisting of a shapeless mass of uniform positive electrification.

Cathode Rays

Rays investigated by J.J. Thomson in the late 1890s that were determined to be electrons.