Ch. 4 Guided Reading
4.1 Introduction to Atoms
Guided Reading and Study
Use Target Reading Skills
Sample questions and answers:
Q. What particles are in the center of an atom?
A. Protons and neutrons.
Q. What particles move around the outside of
the nucleus?
A. Electrons.
1. False
2. a, c, d
3. True
4. J. J. Thomson
5. gold-foil experiment
6. Protons
7. Niels Bohr
8. Neutron
9. False
10. a, b
11. a. nucleus
b. neutron
c. proton
d. electron cloud
12. The number of protons in an atom equals
the number of electrons. The positive charge
from the protons balances the negative charge
from the electrons, making the atom neutral.
13. protons and neutrons
14. The mass of an electron is about 1/2,000
(Or 1/1,836) of the mass of a proton.
15. protons
16. The atomic number is the number of
protons in the nucleus.
17. Isotopes are atoms with the same
number of protons but with a different
number of neutrons.
18. Student diagrams should indicate any two
of the following: An isotope of carbon with a
mass number of 12 has 6 protons, 6 neutrons,
And 6 electrons. An isotope of carbon with a
mass number of 13 has 6 protons, 7 neutrons,
and 6 electrons. An isotope of carbon with a
mass number of 14 has 6 protons, 8 neutrons,
and 6 electrons.
4.2 Organizing the Elements
Guided Reading and Study
1. He recognized a set of patterns that applied
to all elements.
2. The atomic mass of an element is the
average mass of all the isotopes of that element.
3. Patterns appeared when he arranged the
elements in order of increasing atomic mass.
4. true
5. three
6. in a regular, repeated pattern
7. periodic table
8. atomic number
9. The properties of an element can be
predicted from its location in the periodic table
10. period
11. true
12. b, c
13. b
14. Each calcium atom has 20 protons and 20
electrons.
15. chemical symbol
16. The symbols of some elements come from
their Latin names.
17. a. Tin
b. Sn
c. 118.69
d. 50
4.3 Metals
Guided Reading and Study
1. properties
2. c
3. d
4. c
5. b
6. a
7. magnetic
8. true
9. corrosion
10. The reactivity of metals tends to decrease
from left to right across the periodic table
11. a, b
12. sodium and potassium
13. a, b, c
14. magnesium and calcium
15. a, c, d
16. true
17. false
18. They are placed below the periodic table.
19. They are located below the lanthanides
20. uranium
21. a. Alkali
b. Alkaline
c. Transition
d. Lanthanides
22. They are synthesized when nuclear particles
are forced to crash into one another.
23. curium.
24. false
4.4 Nonmetals and Metalloids
Guided Reading and Study
1. nonmetals
2. They are located to the right of the
metalloids.
3. true
4. a, b
5. compounds
6. b
7. All living things contain compounds that
are made of molecules having chains of carbon
atoms.
8. d
9. nitrogen gas
10. diatomic molecule
11. d
12. a, c, d
13. b
14. true
15. b, d
16. a. Group 14; Carbon
b. Group 15; Nitrogen, phosphorus
c. Group 16; Oxygen, sulfur, selenium
d. Group 17; Fluorine, chlorine, bromine,
iodine
e. Group 18; Helium, neon, argon,
krypton, xenon, radon
17. A hydrogen atom has only one proton and
one electron.
18. The chemical properties of hydrogen differ
very much from those of other elements.
19. Metalloids are elements that have some
characteristics of both metals and nonmetals.
20. silicon
21. Their most useful property is their varying
ability to conduct electricity.
22. Semiconductors are substances that can
conduct electricity under some conditions but
not under other conditions.
4.5 Radioactive Elements
Guided Reading and Study
1. radioactive decay
2. Henri Becquerel discovered radioactive
decay while studying a sample of a mineral
containing uranium.
3. A sample of the mineral containing
uranium and a photographic plate wrapped
in paper
4. The image of the mineral rock was on the
photographic plate.
5. radiation
6. They concluded that a reaction was taking
place within the uranium nuclei.
7. radioactivity
8. a. Two protons and two neutrons; positive
b. One electron; negative
c. High-energy waves; neutral
9. a. Gamma radiation
b. Beta decay
c. Alpha decay
10. alpha particles
11. gamma radiation
12. b, c, d
13. Radioactive isotopes release energy and
they give off detectable radiation.
14. Radioactive isotopes that can be followed
through the steps of a chemical reaction or an
industrial process
15. They give off radiation that can be
detected.
16. a, b
17. A tracer used by the bones is injected into
the body. Technicians use radiation-detecting
equipment to make images of the bones.
18. Radioactive iodine is given to patients
with thyroid tumors. The isotope collects
in the thyroid gland and kills tumor cells.