Download Day 2 Guided Reading Chapter 4

Guided Reading From Physical Science Text Chapter 4 and Chapter 4 Slide Show
Ancient Greek Models of Atoms (page 100)
1. Democritus named the smallest particles of matter _____________________ because
they could not be divided.
2.
List the four elements that Aristotle included in his model of matter.
Dalton’s Atomic Theory (page 101)
3. T or F Dalton gathered evidence for the existence of atoms by measuring the masses of
elements that reacted to form compounds.
4. What theory did Dalton propose to explain why the elements in a compound always join
in the same way?
5. Which of the following sentences represent the main points of Dalton’s theory of atoms?
a) All elements are composed of atoms.
b) In a particular compound, atoms of different elements always combine the same way.
c) All atoms have the same mass.
d) Compounds contain atoms of more than one element.
Thomson’s Model of the Atom (pages 102-103)
6. Objects with like electric charges _______________________ , and objects with
opposite electric charges ______________________ .
7. What happened to the beam when Thomson placed a pair of charged metal plates on
either side of the glass tube?
8. Thompson concluded that the particles in the glowing beam had a(n)
__________________ charge because they were attracted to a positive plate.
9. T or F Thompson’s experiments provided the first evidence for the existence of
subatomic particles.
10. Describe Thompson’s model.
Rutherford’s Atomic Theory (pages 104-105)
11. What is an alpha particle?
12. Rutherford’s Hypothesis was that most particles would travel in a ___________ path
from their source to a screen that lit up when struck. Particles that did not pass straight
through would be __________________________________.
13. Which of the following describe what happened when Marsden directed a beam of
particles at a piece of gold foil.
a) Fewer alpha particles were deflected than expected.
b) More alpha particles were deflected than expected.
c) None of the alpha particles were deflected.
d) Some alpha particles bounced back toward the source.
14. Rutherford concluded from the gold foil experiment that an atom’s positive charge is
concentrated in its ________________________.
Properties of Subatomic Particles (pages 109-110)
15. What are the three subatomic particles?
16. Which subatomic particle has a positive charge?
17. Why did Chadwick conclude that the particles produced by his experiment were neutral
in charge?
Comparing Subatomic Particles (pages 109-110)
18. Which of the following are properties that vary among the subatomic particles?
a) Color
b) mass
c) charge
d) location in the atom
19. What is the mass of a neutron compared to that of a proton?
Atomic Number and Mass Number (page 110)
20. T or F Two atoms of the same element can have different numbers of protons.
21. What is an atomic number?
22. Which of the following quantities are always equal to an element’s atomic number?
a) number of nuclei
b) number of protons
c)number of neutrons
d) number of electrons
23. T or F Two different elements can have the same atomic number.
24.What is the mass number of an atom?
25. Number of neutrons = __________________ - _________________
Isotopes (page 112)
26. Every atom of a given element has the same number of ______________ and _________.
27. Every atom of a given element does not have the same number of _____________.
28. What are isotopes?
29. All atoms of oxygen have 8 protons. How many neutrons does oxygen-18 have?
30. T or F Isotopes of oxygen have different chemical properties.
31. Water that contains hydrogen-2 instead of hydrogen-1 atoms is called______________.
Bohr’s Model of the Atom (pages 113-116)
32. Unlike Rutherford’s model of the atom, Bohr’s model focused on which subatomic
particle?
33. T or F In Bohr’s model of the atom, electrons have a constant speed and moved in fixed
orbits around the nucleus.
34. What can happen to the electron of an atom when the atom gains or loses energy?
35. What evidence do scientists have that electrons can move from one energy level to
another?
36. T or F When electrons release energy, some of the energy may be released as visible
light.
Electron Cloud Model (page 116)
37. T or F Bohr’s model was correct in assigning energy levels to electrons.
38. When trying to predict the locations and motions of electrons in atoms, scientists must
work with _______________.
39. What is an electron cloud?
40. T or F Scientists use the electron cloud model to describe the exact location of electrons
around the nucleus.
Atomic Orbitals (page 117)
41. T or F An orbital is a region of space around the nucleus where an electron is likely to
be found.
42. An electron model is a good approximation of ________________________________.
Use the table to answer questions 43 and 44.
43. Higher energy levels have ______________ orbitals than lower energy levels do.
44. What is the relationship between the number of orbitals and the maximum number of
electrons in an energy level?
Electron Configuration (page 118)
45. What is an electron configuration?
46. How many energy levels are needed for a lithium atom’s three electrons when the atom is
at its ground state?
47. T or F An excited state is less stable than a ground state.
48. Which if the following is true when all of the electrons in an atom are in orbitals with the
lowest possible energies?
a) The electrons are in the most stable configuration.
b) The electrons are in an unstable configuration.
c) The atom is in an excited state.
d) The atom is in its ground state.