Download Name Per ___ Reading Assignment – Chapter 4 pages 100

Name ___________________________ Per ___
Reading Assignment – Chapter 4 pages 100 -123
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.
a. ______________b. ____________________ c. ________________________ d. _______________________
Dalton’s Atomic Theory (page 101)
3. Is the following sentence true or false? John 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. Circle the letters of the sentences that 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. Thomson concluded that the particles in the glowing beam had a(n) __________ charge because they were attracted to a positive
plate.
9. Is the following sentence true or false? Thomson’s experiments provided the first evidence for the existence of subatomic particles.
_________________
10. Describe Thomson’s model. _____________________________________________________________________________
Rutherford’s Atomic Theory (pages 104–105)
11. What is an alpha particle? ______________________________________________________________________________
12. Fill in the table to show what Rutherford hypothesized would happen to the paths of alpha particles as they passed through a
thin sheet of gold.
Rutherford’s Hypothesis
Most particles would travel ________________________ from their source to a screen that lit when struck.
Particles that did not pass straight through would be ________________________________
.
13. Circle the letters of the sentences that 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. what did Rutherford concluded from the gold foil experiment. ________________________________________________
What I know about Atoms? ________________________________________________________________________________
What I want to learn about atoms? ___________________________________________________________________________
What I have learned about atoms. ____________________________________________________________________________
Properties of Subatomic Particles (pages 108–109)
1. What are three subatomic particles?
a. ___________________________ b. ___________________________ c. __________________________________
2. What is a subatomic particle with a positive charge called ____________________________
3. Why did Chadwick conclude that the particles produced by his experiment were neutral in charge?
Comparing Subatomic Particles (pages 109–110)
4. Circle the letters of properties that vary among subatomic particles.
a. color
b. mass
c. charge
d. location in the atom
5. Circle the letter of the expression that accurately compares the masses of neutrons and protons.
a. mass of 1 neutron = mass of 1 proton
b. mass of 2000 neutrons = mass of 1 proton
c. mass of 1 electron = mass of 1 proton
d. mass of 1 neutron = mass of 1 electron
Atomic Number and Mass Number (page 110)
6. Is the following sentence true or false? Two atoms of the same element can have different numbers of protons.
________________
7. What is an atomic number? ___________________________________________________________________________
8. Circle the letters that identify quantities that 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
9. Is the following sentence true or false?
Two different elements can have the same atomic number.
10. What is the mass number of an atom? __________________________________________________________________
11. Complete the equation in the table below.
Number of neutrons = _______________________________- ___________________________________
Isotopes (page 112)
12. Every atom of a given element has the same number of ___________________and _______________________.
13. Every atom of a given element does not have the same number of _________________________________________
.
14. What are isotopes? _____________________________________________________________________________
15. All oxygen atoms have 8 protons. Circle the letter of the number of neutrons in an atom of oxygen-18.
a. 8
b. 9
c. 10
d. 18
16. Is the following sentence true or false? Isotopes of oxygen have different chemical properties. ____________________
17. Water that contains hydrogen-2 atoms instead of hydrogen-1 atoms is called . __________________________________
18 What did J.J. Thomson demonstrate about electrons?
A.
That they have a negative electric charge B. That they have a positive electric charge
B.
That they are repelled by a positively charged object D. That they are attracted to a negatively charged object
Review for the test is page 121 and 122 Assessment. You need to be sure to go over this prior to our test over this material
Words to know for this chapter
Proton
___________________________________________________________________________
ground state. ___________________________________________________________________________________
Neutron
____________________________________________________________________________
mass number ___________________________________________________________________________
Nucleus
________________________________________________________________________ ____
energy levels ___________________________________________________________________________
isotopes
____________________________________________________________________________
electron cloud __________________________________________________________________________
atomic number __________________________________________________________________________
orbital
_________________________________________________________________________
Essay Write the answer to each question on a separate sheet of paper.
1. Why did Rutherford propose a new model of the atom after seeing the results of the gold foil experiment?
2. A sample of calcium contains calcium-40, calcium-44, calcium-42, calcium-48, calcium-43, and calcium-46 atoms. Explain why these
atoms can have different mass numbers, but they must have the same atomic number.
3. Why is Bohr’s model of the atom often called the planetary model?
4. What is the difference between an orbital and the electron cloud?
5. Explain what the colors in a fireworks display reveal about the movement of electrons in atoms.