Developing Atomic Theories and Properties of Matter

Vocabulary flashcards covering atomic theories, atomic models, subatomic structure, physical and chemical properties, and classification of matter.

Atomists

Early Greeks who believed that all matter was made of only four things: Earth, fire, water, and air.

John Dalton

British chemist ($1766$–$1844$) who proposed Dalton's Atomic Theory in $1808$ and created the Billiard Ball Model.

Billiard Ball Model

Atomic model proposed by John Dalton in $1808$, stating that all matter is made up of small, indivisible particles called atoms.

J.J. Thomson

British physicist ($1856$–$1940$) who proposed the Plum Pudding Model (aka Raisin Bun Model) and demonstrated that atoms contain sub-atomic particles.

Plum Pudding Model

Also known as the Raisin Bun Model, J.J. Thomson's atomic model depicting negative charges embedded in an evenly distributed positive charge.

Ernest Rutherford

New Zealand physicist ($1871$–$1937$) who proposed the Nuclear Model (aka Beehive Model).

Nuclear Model

Also known as the Beehive Model, Ernest Rutherford's model showing an atom as mostly empty space with a small, dense, positively charged nucleus surrounded by orbiting electrons.

Niels Bohr

Danish physicist ($1885$–$1962$) who proposed the Bohr Model, stating that electrons orbit the nucleus in specific energy levels.

Quantum Mechanical Model of the Atom

The working model of the atom ($1940$) stating that each electron is a cloud of negative charge surrounding the nucleus at a particular energy level.

Nucleons

Particles found in the nucleus of an atom, specifically protons ($p^+$) and neutrons ($n^0$).

Physical Properties

Characteristics describing the physical appearance and composition of a substance, which can be observed without changing its chemical identity.

Malleability

A physical property defining the ability of a substance to be rolled into sheets without crumbling.

Ductility

A physical property defining the ability of a substance to stretch into a wire without breaking.

Chemical Properties

Characteristics describing the reactivity of a substance, which can only be observed through chemical reactions.

Flash Point

A chemical property referring to the temperature required to ignite a flame.

Matter

Anything that has mass and volume.

Pure Substances

Matter characterized by constant physical and chemical properties.

Elements

A type of atom that cannot be chemically broken down into simpler substances.

Compounds

Substances composed of two or more elements bonded together, which can be chemically separated into simpler substances.

Mechanical Mixtures

Heterogeneous mixtures in which different parts are visible and often exist in different phases.

Solution

A homogeneous mixture in which components are dissolved together, not visible, and maintain a constant composition throughout.