4.1. Evolution of the Atomic Model http://www.ck12.org
Lesson Review Questions
- Compare and contrast the continuous theory of matter with the discontinuous theory of matter.
- Which of the following did Proust discover?
a. Elements combine in unpredictable ratios with other elements.
b. The mass of an element is always changing even when combined with another element.
c. Chemical compounds always contain the same proportion of elements by mass, regardless of amount.
d. Elements combine only in fixed ratios based on volume, but not mass. - Which of the following did Lavoisier discover?
a. When matter reacts, there is a small portion that is lost and unaccounted for.
b. For an isolated system, the mass of the reactants must equal the mass of the products.
c. When matter reacts, there can be mass that comes from nowhere and is unaccounted for.
d. Mass cannot be accurately accounted for in chemical processes. - What did John Dalton discover about chemical compounds? How did his theory differ from Proust’s?
- Summarize Dalton’s atomic theory.
- What were two points made by Dalton’s atomic theory that are no longer considered correct?
Further Reading / Supplemental Links
- Kotz, John, and Heith Purcell. 1991. Chemistry Chemical Reactivity. Orlando, FL: Holt, Rinehart and
Winston. - Partington, J. R. 1989. A Short History of Chemistry. 3 ed. New York: Macmillan. Reissued by Dover
Publications.
Points to Consider
- In this lesson, we discussed the early evolution of theories about the atom. More recent evidence has shown
that the atom is comprised of subatomic particles that exhibit unique properties and affect the overall behavior
of an atom. In our next lesson, we will look at subatomic particles, including how they were discovered and
how they behave.