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1.1 Early Ideas of the Atom
Review Questions
1. It turns out that a few of the ideas in Dalton’s atomic theory aren’t entirely correct. Are inaccurate theories an
indication that science is a waste of time?
1. Match the person, or group of people, with their role in the development of chemistry.
(a) early Greek philosophers (i) suggested that all matter was made up of tiny, indivisible objects
(b) John Dalton
(ii) relied on logic to understand the world around them
(c) Democritus
(iii) proposed the first scientific theory relating chemical changes to the structure, properties, and
1. Which of the following is notpart of Dalton’s Atomic Theory?
a.
b.
c.
d.
Matter is made of tiny particles called atoms.
During a chemical reaction, atoms are rearranged.
During a nuclear reaction, atoms are split apart.
All atoms of a specific element are the same.
2. What is the greatest advantage Dalton’s atomic theory had over Democritus’s?
3. Choose one of the commonly believed topics from the list below (or choose your own): air, genes, global
warming, gravity, trust, or UV rays. If you had to make a case proving that this concept really exists, how
would you prove it?
a.
b.
c.
d.
Which topic did you pick?
Can you SEE it? Explain.
What observations can you make about this topic? What effects do you see because of this?
There are other things we never see with our own two eyes, yet we still know things about them. List
some examples here. How do we know things really exist like we believe they do?
1.1. Early Ideas of the Atom
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1.2 Further Understanding of the Atom
Review Questions
1. Decide whether each of the following statements is true or false.
a.
b.
c.
d.
e.
Cathode rays are positively charged.
Cathode rays are rays of light, and thus they have no mass.
Cathode rays can be repelled by a negatively charged metal plate.
J.J. Thomson is credited with the discovery of the electron.
Phosphor is a material that glows when struck by cathode rays.
In Table 1.1, match each conclusion with the observation/data that supports it.
TABLE 1.1: Table for questions 2-7
Conclusion
2. All atoms have electrons
3. Atoms are mostly empty space.
4. Electrons have a negative charge
5. In any chemical reaction, the total mass does not
change
6. The nucleus is positively charged
7. Atoms have a small, dense nucleus
Observations
(a) Most alpha particles shot at gold foil go straight
through, without any change in their direction.
(b) A few alpha particles shot at gold foil bounce in
the opposite direction.
(c) Some alpha particles when shot through gold foil
bend away from the gold.
(d) No matter which element Thomson put in a
cathode ray tube, particles with the same properties
(such as charge & mass) were ejected.
(e) In a sealed container, if a piece of wood is burned
or a piece of iron rusts, the mass of the stuff in the
container before the any changes occur is always
equal to the mass at the end.
(f) The particles ejected in Thomson’s experiment
bent away from negatively charged plates, but toward positively charged plates.
1. What is the name given to the tiny clump of positive material at the center of an atom?
2. Electrons move ______ negatively charged metals plates and ______ positively charged metal plates.
3. A sodium cationis a sodium atom that has lost one of its electrons. Answer each of the following regarding a
sodium cation.
a. Would the charge on a sodium cation be positive, negative or neutral?
b. Would sodium cations be attracted to a negative metal plate, or a positive metal plate?
c. Would electrons be attracted to or repelled from sodium cations?
Consider the following two paragraphs for questions 11-14.
Scientist 1: Although atoms were once regarded as the smallest part of nature, they are composed of even smaller
particles. All atoms contain negatively charged particles called electrons. However, the total charge of any atom
is zero. Therefore, this means that there must also be positive charge in the atom. The electrons sit in a bed of
positively charged mass.
Chapter 1. Atoms and Atomic Structure
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Scientist 2: It is true that atoms contain smaller particles. However, the electrons are not floating in a bed of positive
charge. The positive charge is located at the central part of the atom in a very small, dense mass called a nucleus.
The electrons are found outside of the nucleus.
1. What is the main dispute between the two scientists’ theories?
2. Another scientist was able to calculate the exact charge of an electron to be −1.6 × 10−19 C. What effect does
this have on the claims of Scientist 1? (Pick one answer.)
a. Goes against his claim
b. Supports his claim
c. Has no effect on his claim
3. Another scientist was able to calculate the exact charge of an electron to be −1.6 × 10−19 C. What effect does
this have on the claims of Scientist 2? (Pick one answer.)
a. Goes against his claim
b. Supports his claim
c. Has no effect on his claim
4. If a positively charged particle was shot at a thin sheet of gold foil, what would the second scientist predict
will happen?
1.2. Further Understanding of the Atom
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1.3 Atomic Structure
Review Questions
Decide whether each of the following statements is true or false.
1.
2.
3.
4.
5.
The nucleus of an atom contains all of the protons in the atom.
The nucleus of an atom contains all of the neutrons in the atom.
The nucleus of an atom contains all of the electrons in the atom.
Neutral atoms of a given element must contain the same number of neutrons.
Neutral atoms of a given element must contain the same number of electrons.
In Table 1.2, match the subatomic property with its description.
TABLE 1.2: Table for Questions 6-8
Sub-Atomic Particle
6. electron
7. neutron
8. proton
Characteristics
(a) has an atomic charge of +1
1
(b) has a mass of approximately 1840
amu
(c) is neither attracted to nor repelled from charged
objects
1. Arrange the electron, proton, and neutron in order of decreasing mass.
Indicate which of the following statements is true or false.
1.
2.
3.
4.
5.
6.
An element’s atomic number is equal to the number of protons in the nucleus of any of its atoms.
A neutral atom with 4 protons must have 4 electrons.
An atom with 7 protons and 7 neutrons will have a mass number of 14.
An atom with 7 protons and 7 neutrons will have an atomic number of 14.
A neutral atom with 7 electrons and 7 neutrons will have an atomic number of 14.
Use the periodic table to find the symbol for the element with:
a.
b.
c.
d.
44 electrons in a neutral atom.
30 protons.
an atomic number of 36.
an atomic weight of 14.007 amu.
If you need a periodic table, you can visit this website: http://www.ptable.com/.
In Table 1.3, Column One contains data for five different elements. Column Two contains data for the same five
elements, but for different isotopes of those elements. Match the columns by connecting isotopes of the same element.
TABLE 1.3: Table for Questions 16-20
Original element
16. an atom with 2 protons and 1 neutron
17. a Be (beryllium) atom with 5 neutrons
Isotope of the same element
(a) a C (carbon) atom with 6 neutrons
(b) an atom with 2 protons and 2 neutrons
Chapter 1. Atoms and Atomic Structure
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TABLE 1.3: (continued)
Original element
18. an atom with an atomic number of 6 and mass
number of 13
19. an atom with 1 proton and a mass number of 1
20. an atom with an atomic number of 7 and 7
neutrons
1.
2.
3.
4.
Isotope of the same element
(c) an atom with an atomic number of 7 and a mass
number of 15
(d) an atom with an atomic number of 2 and 1
neutron
(e) an atom with an atomic number of 4 and 6
neutrons
What’s the atomic number of an atom that contains 13 protons and 13 neutrons?
What’s the mass number of an atom that contains 24 protons and 30 neutrons?
What’s the mass number of the isotope of manganese (Mn) containing 28 neutrons?
What’s the atomic number of the isotope of calcium (Ca) containing 20 neutrons?
Write the nuclear symbol for each element described:
1. 32 neutrons in an atom with mass number of 58
2. an atom with 10 neutrons and 19 protons
Indicate the number of protons, neutrons, and electrons in each of the following atoms:
1.
2.
3.
4.
5.
6.
7.
8.
4 He
2
sodium-23
1H
1
iron-55
37 Cl
17
boron-11
238 U
92
uranium-235
Copy Table 1.4 and fill in the missing information.
TABLE 1.4: Table for questions 35-39
35.
36.
37.
38.
39.
Name (with
mass)
silver-108
Nuclear
Symbol
91
40 Zr
Mass Number
12
Atomic
Number
6
Number of
Protons
11
Number of
Electrons
Number of
Neutrons
12
cesium-133
1. Copper has two naturally occurring isotopes. 69.15% of copper atoms are Cu-63 and have a mass of 62.93
amu. The other 30.85% of copper atoms are Cu-65 and have a mass of 64.93 amu. What is the atomic weight
of copper? Show all work in your calculation.
2. Chlorine has two isotopes, Cl-35 and Cl-37. Their abundances are 75.53% and 24.47% respectively. Calculate
the atomic weight of chlorine. Show all work in your calculation.
3. An unknown element is found with the following masses and relative abundances: 75.53% have a mass of
34.96885 amu, and 24.47% have a mass of 36.9590 amu. What is the atomic weight of the element? Based
on this evidence, which element is it?
1.3. Atomic Structure
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1.4 The Nature of Light
Review Questions
1.
2.
3.
4.
Name at least three different areas in the spectrum of electromagnetic radiation.
Which color of visible light has the longer wavelength, red or blue?
What is the relationship between the energy of electromagnetic radiation and the frequency of that radiation?
Of the two waves drawn below, which one has the most energy? How do you know?
5. List the following parts of the electromagnetic spectrum in order of INCREASING energy: radio, infrared,
visible light, UV, gamma, microwaves
6. List the visible colors of light in order of INCREASING energy.
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1.5 Atoms and Electromagnetic Spectra
Review Questions
1. What is the general relationship between the energy of an electron energy level and its distance from the
nucleus?
2. According to Bohr’s theory, how can an electron gain or lose energy?
3. What happens when an electron in an excited atom returns to its ground state?
4. Bohr’s model of the atom is frequently referred to as the “quantum model.” Why? What does it mean to be
quantized? How are electrons in atoms quantized?
5. Why do the electrons of an element release only a specific pattern of light? Why don’t they produce all colors
of light?
6. Each element produces a unique pattern of light due to different energies within the atom. Why would this
information be useful in analyzing a material?
7. It was known that an undiscovered element (later named helium) was on the sun before it was ever discovered
on Earth by looking at the sun’s spectrum. How do scientists know that the sun contains helium atoms when
no one has even taken a sample of material from the sun?
8. You have looked at emission spectra. Electrons can also absorb energy, forming an absorption spectrum. What
would an absorption spectrum look like? Why do you say that?
9. Use the following terms to explain how an electron releases a photon of light: electron, energy level, excited
state, ground state, photon. Draw a picture if it is helpful.
1.5. Atoms and Electromagnetic Spectra
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1.6 Electron Arrangement in Atoms
Review Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Which energy level holds a maximum of eight electrons?
Which energy sublevel holds a maximum of six electrons?
Which energy sublevel holds a maximum of ten electrons?
If all the orbitals in the first two energy levels are filled, how many electrons are required?
In which energy level and sublevel of the carbon atom is the outermost electron located?
How many electrons are in the 2p energy sublevel of a neutral nitrogen atom?
Which element’s neutral atoms will have the electron configuration: 1s2 2s2 2p6 3s2 3p1 ?
What energy level and sublevel immediately follow 5s in the filling order?
What is the outermost energy level and sublevel used in the electron configuration of potassium?
Which element will have the following electron configuration: 1s2 2s2 2p6 3s2 3p2 ?
Write electron configurations for each of the following neutral atoms:
1.
2.
3.
4.
5.
6.
7.
8.
Magnesium
Nitrogen
Indium
Yttrium
Tin
Xenon
Cesium
Uranium
Write the abbreviated electron configuration for each of the following neutral atoms:
1.
2.
3.
4.
5.
Fluorine
Aluminum
Titanium
Arsenic
Rubidium
Chapter 1. Atoms and Atomic Structure