Modern Atomic Theory and Foundational Laws

Vocabulary flashcards covering the historical laws of chemistry, Dalton's atomic theory, and the fundamental properties of atoms and compounds.

Law of conservation of mass

A law formulated by Antoine Lauser stating that in a chemical reaction, matter is neither created nor destroyed, meaning the total mass of the reactants will always equal the total mass of the products.

Antoine Lauser

The scientist who formulated the law of conservation of mass.

Law of definite proportions

Also referred to as constant compositions, a law formulated by Joseph Proust stating that a sample of a given chemical compound, regardless of its source or preparation method, is composed of the exact same elements in the exact same proportions by mass.

Joseph Proust

The scientist who formulated the law of definite proportions (constant compositions).

Dalton's atomic theory

The first modern atomic theory, formulated by John Dalton using the law of conservation of mass and the law of definite proportions to explain why both laws were true.

Atoms

Extremely small, indivisible, and indestructible particles that comprise each element.

Atoms of the same element (Dalton's postulate)

The principle stating that all atoms of a given element are identical, possessing the same mass and identity properties that distinguish them from atoms of other elements.

Isotopes

Atoms of the same element that have different masses.

Compounds

Substances formed when atoms combine in simple whole number ratios, which prevents the existence of fractions or half an atom in a molecule.

Chemical reactions (Atomic arrangements)

Processes wherein atoms of one element cannot change into atoms of another; atoms are simply separated, combined, and rearranged, and are never created nor destroyed.