Download 4-1 Introduction to Atoms Directed Reading Questions

4-1 Introduction to Atoms Directed Reading Questions
Directions: As you read 4-1, answer the following questions on a separate piece of
paper.
1. How is the painting in figure 1 like matter? Like these images, matter is made of
tiny parts called atoms. (p. 124)
2. Why have the shape and structure of atoms changed many times? Because atoms
are so small, studying them is difficult since they are hard to see. (p. 125)
3. Why was the term “atomos” appropriate for the modern term “atom”? “Atomos”
means “uncuttable” and an atom is the smallest particle of an element. (p. 125)
4. State the summary of Dalton’s ideas. See Figure 2. (p. 125)
5. How is Thomson’s proposed model of an atom similar to raisin bread? Thomson
suggested that atoms had negatively charged electrons embedded in a positive
sphere, like raisins or berries in a muffin. (p. 126)
6. What did Rutherford observe when he sent a beam of positively charged particles
toward gold foil? Most of the particles passed through the foil with little or no
deflection. A few particles were deflected strongly. (pp. 126-127)
7. How was Rutherford’s atomic model influenced by his experimental evidence?
Rutherford’s evidence suggested that the positive charge in the atom was
concentrated in a tiny region of the atom. In Rutherford’s model, an atom is
mostly empty space with a positively charged nucleus in the center. With this
structure, most positive particles would pass through with little or no deflection
(pp. 126-127)
8. If Thomson’s model was correct, what would Rutherford have observed? The
charged particles would pass right through the foil in a straight line. (p. 126)
9. If the solar system represents an atom, which part of the atom does the sun
represent? Nucleus
Which parts of the atom do the planets represent? Electrons (p. 127)
10. How are electrons in Bohr’s model like planets in the solar system? They move
around the nucleus in specific orbits (p. 127)
11. Why was the idea of an “electron cloud” created? A visual model showing where
electrons are located (p. 127)
12. What is a neutron? A subatomic particle with no charge
Why don’t they affect the overall charge of an atom? Neutrons do not affect the
charge of an atom because they have no charge. (p. 128)
13. Why is an atom’s overall charge neutral? The charges from the protons (+) and
electrons (-) balance making the atom neutral. (p. 128)
14. What does the modern atomic theory state? At the center of the atom is a nucleus
containing protons and neutrons. Surrounding the nucleus is a cloudlike region of
moving electrons. (p. 128)
15. T/F. 1 proton and 1 electron will be the same relative mass (amu). T, a proton and
neutron are about equal in mass. (p. 129)
16. T/F. Every atom of a given element has the same number of protons. T (p. 129)
17. Why do all atoms have their own atomic number? The definition of the element is
based on its atomic number (p. 129)
18. What are isotopes? Atoms of the same element with a different number of
neutrons (p. 130)
19. Look at figure 10. Which isotope of carbon has the largest mass number? Carbon14 (p. 130)
20. Referring also to figure 10, which isotope contains the most protons? All contain
6 protons (p. 130)