CHEM TALK Activity 3 ATOMIC MASS
SHORT ANSWER
NAME
PERIOD
1. What is the definition of an atom?
2. Why did Aristotle think that atoms could not exist?
3. What is the root meaning of the word atom?
4. Why could you not prove the concept of an atom by continuing to cut the aluminum foil with your
scissors?
5. What makes up a compound?
6. What likely reason does the author cite for the inaccurate massing of elements by early chemist?
7. How does the term “ratio” relate to Dalton’s work with gases such as oxygen, nitrogen and hydrogen?
8. Why do you think that Dalton’s work did not involve the noble gases?
9. Dalton’s “parts of oxygen to parts of hydrogen in water” is based on their relative masses. On what
did Gay-Lussac base his water ratio of hydrogen being twice that of oxygen?
10. Compounds do not always have equal numbers of each type of atom in them. Name the famous
scientist who is given credit for helping make corrections in chemical formulas and masses?
11. After learning about some of the early chemist and their dedication to advancing an understanding
of atoms and compounds, how do you feel about your chemical adventure in masses the substances in
your experiment?
12. How did chemists determine the relative masses of atoms?
13. What is meant by the term “relative masses”?
14. How many times more massive is carbon than hydrogen?
15. Find the two numbers in the block for these elements that have a relative ratio of about twelve to
one. These numbers represent the masses of these elements. What is the correct unit for these masses?
16. Mendeleev is given credit for an early version of the periodic table. What information did he use to
arrange his elements in his table?
17. Explain the Law of Definite Proportions.
18. Use the Law of Definite Proportions to explain why a given mass of magnesium reacting with plenty
of copper (II) chloride should always yield a specific mass of copper.