Corpuscles to Chemical Atomic Theory (The Development of Atomic Theory)
Amedeo Avogadro
(the man who conceptualized the mole) determined that equivalent volumes of two gases under similar conditions contained equal numbers of particles, and that differences in their masses was a result of a difference in their molecular mass. Thus, he figured out a reliable way of weighing atoms and molecules. This was something Dalton lacked in his theory.
3 Fundamental Laws
Antoine Lavoisier's Law of Conservation of Mass • Joseph Proust's Law of Definite Proportions • John Dalton's Law of Multiple Proportions
Antoine Lavoisier's Law of Conservation of Mass
During chemical change, matter is neither created or destroyed
John Dalton (1766-1844)
His Chemical Atomic Theory merged the concepts of the atom and element, and formally established the two in the practice of chemistry. • Gases, and all chemically inseparable elements, are made of atoms. • The atoms of an element are identical in their masses. • Atoms of different elements have different masses.
Joseph Proust's Law of Definite Proportions
a compound always contains the same elements in certain definite proportions.
Joseph Gay-Lussac
determined that oxygen gas was made of 2 atoms of oxygen and took the form of a molecule instead of an atom. This offered the possibility that an element wasn't necessarily made up of one atom, thus distinguishing the atom from the molecule.
John Dalton's Law of Multiple Proportions
elements can combine in different ways to form different chemical compounds, whose mass ratios are simple whole-number multiples of each other.
chemical element
is a substance that cannot be broken down into simpler components.
Dmitri Mendeleev
published a periodic table of elements that ordered elements according to their atomic weights. He noted patterns in their properties that enabled him to predict the discovery of other elements. His table became the basis of the modern Periodic Table.
Developments in the way we think about both atoms and elements as a result of Dalton's Chemical Atomic Theory
that elements were made of the same atoms and had properties unique to the element, while chemical compounds were made of different combined or compounded atoms, and exhibited different sets of properties. • that one could compute the weights of elements (and their atoms) by looking at comparable amounts of the compounds they formed.
Antoine Lavoisier
used closed vessels and precise weight measurements in many experiments to achieve the following: • He showed that air is not an element because it could be separated into several components. By looking at the air from reacting metals and calces, he found different "types" of air, one of which caused burning to happen. Lavoisier called it oxygen. -He came up with an initial list of 33 elements, and created a systematic way of naming elements and the compounds they created. -•He also wrote the first Chemistry textbook. For this and many other contributions, he became known as the Father of Chemistry.
Robert Boyle's ideas
•Corpuscles were "certain primitive and simple, or perfectly unmingled bodies" that were indivisible and whole. This went against the Aristotelian thinking that objects are made of infinitely divisible elements. It was more like the idea of Democritus and Leucippus. •He recognized elements as the simplest substances that constitute mixtures, and that elements are those that cannot be decomposed into other substances via chemical reactions. •He emphasized the need to observe and test the presence of corpuscles in alchemical experiments.
