1. Corpuscles to Chemical Atomic Theory (The Development of Atomic Theory)

2. Important Key Terms a. Robert Boyle b. corpuscle c. Antoine Lavoisier
d. chemical element
e. John Dalton
f. Chemical atomic theory
g. 3 Fundamental Laws
h. Joseph Gay-Lussac
i. Amedeo Avogadro
j. Dmitri Mendeleev

3. Classification of Matter

4. Robert Boyle
He was a practitioner of alchemy, he was also critical about some of its ideas. Robert Boyle’s ideas:
• Corpuscles were “certain primitive and simple, or perfectly unmingled bodies” that were indivisible

5. 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

6. reactions. He emphasized the need to observe and test the presence of corpuscles in alchemical experiments.
Antoine Lavoisier
He was a French Chemist
Around 1789, he used closed vessels and precise weight measurements in many experiments to achieve the ff.:

7. He disproved the principle of phlogiston, where heated metals were thought to lose a substance of negative weight. Metals, which gain weight when heated in open air, actually react with oxygen air, causing it to form a calx (metal oxide).

8. 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.

9. He showed that water is not an element, because it was made of two substances. Oxygen was found to produce water when burned in the presence of “flammable air” (a part of air that would be later called hydrogen).

10. Lavoisier was able to refute Aristotle’s thinking of a universe composed of three or four elements. He had proof of Boyle’s concept of a simple substance, now known as the chemical element.
A chemical element is a substance that cannot be broken down into simpler components.

11. He defined a compound as a substance composed of these elements
He defined a compound as a substance composed of these elements. 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.

12. John Dalton ( )
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.
Atoms combine in small, whole number ratios.

13. Dalton proposed his atomic theory as the best explanation to three important observations made at the time. These three observations were replicable results of experiments done by different scientists. Since we have enough evidence to establish these observations as consistently occurring under certain conditions of nature, they are now known as laws, namely, the 3 Fundamental Laws:
• Antoine Lavoisier’s Law of Conservation of Mass

14. Dalton’s Chemical Atomic Theory:
• Joseph Proust’s Law of Definite Proportions
• John Dalton’s Law of Multiple Proportions
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.
• that one could compute atomic weights compared to a reference. Dalton set the atomic weight of hydrogen to 1 as this reference. For this reason, the unit for atomic weight was called the dalton for some time (it is now called the AMU or atomic mass unit).
However, given the technology at the time, the number of atoms in different compounds was not known. For example, water was known to be formed from hydrogen and oxygen, but not in the ratio 2:1, so many calculations of atomic weight were inaccurate.

15. Other scientists who made headway in the concept of the element thanks to Dalton’s theory

16. Joseph Gay-Lussac
He 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.

17. 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.

18. Dmitri Mendeleev
He 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. • Many other scientists in the 19th century discovered more elements, thanks to Dalton’s theory, Mendeleev’s table, and the advent of improved analytical and decomposition techniques. From Lavoisier’s 33 elements, the century ended with 82.

19. Mendeleev's 1871 periodic table

20. A c t i v i t y
Rough timeline completion The historical development of the atom or the chemical element in a timeline. Attach metacards with concepts or names of people or groups. You should add dates and time periods. Dates need not be exact points on the line. You can modify the timeline by adding brackets (e.g. for alchemy spanning several hundred years). Link metacards, use arrows or lines to denote periods, etc. and should accomplish the timeline within 20 minutes, the more detailed the better. Refer to the image below for an incomplete sample.

22. EVALUATION (10 MINS)
1) Which of the following is NOT part of Dalton’s Chemical Atomic Theory? a. All atoms of the same element can have different masses or isotopes. b. Atoms combine only in whole number ratios. c. All elements are made of atoms. d. None of the above

23. Match the contribution in Column A to the person in Column B by writing the letter beside the number:
Column A Column B
2) Definition of chemical element A) Dmitri Mendeleev
3) Concept of corpuscles B) Joseph Proust
4) Law of Multiple Proportions C) John Dalton
5) Some elements are found as molecules D) Robert Boyle
6) Law of Definite Proportions E) Antoine Lavoisier
F) Joseph Gay-Lussac
Answer the following:
7. Father of Chemistry
8. He devised the Periodic Table
9. He determined that oxygen was made of two atoms of oxygen
10. He conceptualized the mole