Historical Development of the Periodic Table and Atomic Theory (Vocabulary)

A set of vocabulary flashcards covering key terms and concepts from the lecture notes on the periodic table, Greek atom theory, Dalton, Schrödinger, and Thomson.

Dmitri Mendeleev

Russian chemist who published the first periodic table in 1869, organizing elements by increasing atomic mass and predicting gaps for undiscovered elements.

Mendeleev's Periodic Table

The first periodic table, showing periodic repetition of chemical properties and containing about 65 elements.

Periodic Table

A tabular arrangement of elements showing periodic recurrence of properties; groups share similar traits.

Atomic Mass

A property used to order elements in Mendeleev’s table; reflects the mass of an atom.

Periodicity

The repeating pattern of chemical properties across periods and groups in the periodic table.

Alkali Metals

Group I elements that react violently with water.

Halogens

Group VII elements that form water-soluble salts.

Noble Gases

Group VIII elements that are generally non-reactive.

Group

A vertical column in the periodic table; elements within a group have similar properties.

John Dalton

Early 19th-century chemist who proposed atoms are composed of identical atoms with unique atomic masses.

Dalton's Atomic Theory

Idea that elements are made of identical atoms with distinct atomic masses.

Indivisible Atom

Older belief that atoms could not be divided into smaller parts.

Hook and Eye Affair / Solid Sphere Model

Early atomic model portraying atoms as indivisible solid spheres (Dalton-era concept).

Four Elements

Ancient Greek concept of matter consisting of Earth, Water, Air, and Fire.

Four Essences

Modification of the four elements: Wet, Dry, Hot, Cold.

Atom (Greek) meaning

Ancient term meaning indivisible.

Leucippus and Democritus

Ancient Greek philosophers who proposed the idea of atoms as indivisible units.

Schrödinger Model

Quantum mechanical model (1926) describing electrons as waves with probability distributions.

Electrons as Waves

Key idea in Schrödinger’s model: electrons exhibit wave-like behavior.

Orbitals

Regions in space where electrons are likely to be found.

Probability Distribution

Schrödinger’s view that electron positions are described by probability, not exact locations.

Bohr Model

Earlier atomic model with electrons in fixed, one-dimensional orbits around the nucleus.

Three-Dimensional Model

Schrödinger’s model describing electron distribution in three dimensions.

J.J. Thomson

Physicist who discovered the electron in the late 1890s (1897) and proposed the plum pudding model.

Cathode Rays

Beams of electrons used in Thomson’s experiments to study atomic structure.

Plum Pudding Model

Thomson’s 1904 model proposing electrons embedded in a positively charged 'pudding'.

Post-Mendeleev Discoveries

Discovery of additional elements after Mendeleev’s table, expanding the periodic table.