An Historical View of the Creation of the Periodic Table

Flashcards covering key historical figures, concepts, and discoveries that led to the creation and understanding of the periodic table, based on the provided lecture notes. This set focuses on vocabulary-style definitions for important terms mentioned in the lecture.

Periodic Table

A system for categorizing elements based on particular key physical and chemical properties, representing a map of the quantum nature of sub-atomic structure.

Homogeneity

A characteristic of a material that is the same throughout, from one side to the other.

Heterogeneous

A characteristic of a material that is different in different places, or not uniform throughout.

Granite

A common rock that is a heterogeneous mixture of different minerals like quartz, feldspar, and biotite mica.

Purity

Often indicated by homogeneity, but homogeneity alone is not sufficient to define a pure substance (e.g., seawater is homogeneous but a mixture).

Native Form (Elements)

Elements that exist on Earth as a pure element, such as gold, silver, and copper.

Gold, Silver, and Copper

Elements known since antiquity because they exist in their native, pure form and are relatively un-reactive.

Mercury

A liquid metal easily liberated from its ore, cinnabar, through thermal decomposition.

Smelting

A chemical process involving heating ores to extract metals, such as obtaining lead, tin, and copper by fire.

Bronze

An alloy formed by combining tin and copper, giving an entire era of human history its name (Bronze Age).

Iron Extraction

A more challenging process requiring heating iron ores (like hematite and magnetite) to about 1500 °C in the presence of carbon and chalk/limestone.

Alchemy

An historical pursuit focused on gaining immortality (philosopher's stone) and turning lead into gold, which also involved early chemical experimentation and observation.

Henning Brand

A German alchemist who discovered phosphorous in 1669, the first element with precisely known discovery details.

Phosphorous

The first element known with precise discovery details, found by Henning Brand; a white waxy solid that shone brightly, meaning 'giver of light'.

Robert Boyle

An Anglo-Irish aristocrat and scientist who, in 'The Sceptical Chemist' (1661), defined 'element' as a substance that cannot be split into other things and 'compound' as a material made from elements.

Elements (Boyle's Definition)

Materials that cannot be split into other simpler substances, no matter what is done to them.

Antoine Lavoisier

Known as the 'Father of Chemistry' for his careful experiments with a precision balance, leading to fundamental postulates about matter and mass.

Conservation of Mass

Lavoisier's principle stating that mass can neither be created nor destroyed in chemical reactions; the total mass at the beginning and end of a reaction remains constant.

John Dalton

A teacher and scientist who proposed the atomic theory and expanded elemental symbolic representations, depicting compounds by combining symbols in particular stoichiometries.

Atomic Theory

Dalton's theory that the world is made of vast numbers of minuscule atoms, with each different type of atom corresponding to a different element and serving as an indivisible minimal subunit.

Johan Wolfgang Dobereiner

Noticed mathematical relationships in groups of three chemically similar elements, calling them 'triads'.

Dobereiner's Triads

Groups of three elements where the mass of the middle element is the mathematical mean of the outer two, and it exhibits intermediate properties and behavior (e.g., Li, Na, K).

John Newlands

Proposed an elemental ordering where similarities in behavior occurred every 8th element (Newlands' Octaves), though his musical analogy was largely rejected.

Newlands' Octaves

John Newlands' theory that elements, when listed by increasing mass, showed similar behavior every 8th element; connection to musical octaves led to its rejection.

Dimitri Mendeleev

Creator of a much more successful periodic table in 1869, which organized elements by increasing characteristic mass and chemical behavior, purposefully leaving gaps for undiscovered elements.

Mendeleev's Periodic Table (1869)

An elemental ordering that organized elements into 8 groups based on increasing mass and similar chemical properties, allowing for the prediction of undiscovered elements and their properties.

Prediction of Elements (Mendeleev)

Mendeleev's successful act of leaving gaps in his periodic table for unknown elements and predicting their mass and chemical behavior, leading others to discover them.