Download Ch. 4-7 Review Answers pg. 3-7

Ch. 4-5 Test Review
CHAPTER 4
Early History
1) Who thought there were 4 types of matter – Earth, Air, Fire, and Water? Ancient Greeks
2) Describe how Democritus and Aristotle differed in their views of the atom. Democritus thought matter
was discrete – it contained a smallest particle which could not be broken down and retain its properties.
Aristotle thought matter was continuous – it could be divided into infinitely smaller pieces.
3) What happened in the late 1700’s that eventually lead to Dalton’s atomic theory? Better balances were
made that could more accurately weigh atomic masses, masses of reactions etc. which lead to the 3 natural
laws – Law of Conservation of Mass, Law of Constant Composition, and Law of Multiple Proportions.
Dalton
1) Describe Dalton’s model of the atom. Dalton thought the atom was a tiny, indivisible particle. He thought
that atoms of the same element were identical, yet differed from atoms of other elements. He thought they
were combined, separated, or rearranged in chemical reactions (not created or destroyed). He thought they
combined in simple whole-number ratios to form compounds.
2) What were the three mistakes in his theory? The atom is divisible (it contains protons, neutrons and
electrons). Atoms of the same element are not identical – atoms of the same element can have different
masses. Atoms can be created or destroyed in nuclear reactions.
Electron Discovery
1) Who discovered it? JJ Thomson
2) With what experiment was it discovered? Cathode Ray Tube Experiment
3) What observations did Thomson make in his experiments? (Hint: 2 main ones)1) The phosphorescent
screen lit up 2) The charged beam was defected by a negative electric field (or attracted to a positive one).
4) What did Thomson calculate that gave him credit for discovering the electron? The charge/mass ratio of
the electron
5) What was the name of Thomson’s model of the atom? Plum Pudding Model
6) Describe Thomson’s model of the atom. His atom was diffuse positive charge with electrons floating
through it.
Charge (and then Mass) of the Electron
1) Who determined the charge of the electron? Robert Millikan
2) With what experiment did he do this? Oil Drop Experiment
3) What was he then able to calculate? The Mass of the electron
4) Did he have a model of the atom? No. He just determined details to add to JJ’s.
Nucleus Discovery
1) Who discovered the nucleus? Ernest Rutherford
2) With what experiment did he do this? Gold Foil Experiment
3) What is the name of the type of particle shot at the gold foil? Alpha particle
4) What kind of charge did the particles have? positive
5) Where did the phosphorescent screen light up? Be specific. It mostly lit up directly behind the gold foil,
but occasionally lit up to the sides
6) What conclusions did he draw from what he saw? The atom contains a concentrated positive charge (the
nucleus) but is mostly empty space.
8) Describe how Thomson’s model was changed after these conclusions. Rather than having diffuse positive
charge throughout the atom, the positive charge was concentrated in the middle as the nucleus. The electrons
surrounded the nucleus moving in empty space.
Other particles
1) Who discovered the proton? Rutherford
2) Who discovered the neutron? James Chadwick
Atomic Structure
1) Name the three main subatomic particles and where they are located. Protons, electrons, neutrons
2) What subatomic particles contribute to the majority of the mass of the atom? Protons and neutrons (both
part of the nucleus which explains #3)
3) What part of the atom is dense? The nucleus (see #2)
4) If an atom is neutral the number of protons and electrons are equal.
5) The charge of the nucleus is equal to the number of protons.
6) You cannot change the number of protons and still have the same element.
7) If you change the number of electrons you get an ion.
The ion is positive/negative if you lose electrons.
The ion is positive/negative if you gain electrons.
8) If you change the number of neutrons that’s called an isotope.
9) What’s the nuclear symbol for an element with 52 protons and 71 neutrons? 12352Te
10) What about an atom’s structure determines its chemical and physical properties? the arrangement of the
electrons
11) How many atoms of hydrogen have a mass of 1.0079 amu? ZERO. (that’s the average mass of the
isotopes.)
12) What element has a mass number of 40 and 21 neutrons? potassium
13) Calculate the average atomic mass of chromium given the table below. 51.99 amu
Isotope
% Abundance
Mass (amu)
Cr-50
4.35%
49.946
Cr-52
83.79%
51.941
Cr-53
9.50%
52.941
Cr-54
2.36%
53.939
14) Complete the following table:
# protons
#
#
Mass # Atomic # Charge Charge
electrons neutrons
atom
nucleus
Na-23
11
11
12
23
11
0
+11
Cr-54
24
24
30
54
+24
0
+24
27
13
13
14
27
13
0
+13
13Al
137
2+
Ba
56
54
81
137
56
2+
+56
56
31
216
18
15
31
16
2+16
16S
55
25
25
30
55
25
0
+25
25Mn
40
18
18
22
40
18
0
+18
18Ar
23
+
11
10
12
23
11
+1
+11
11Na
Radioactivity
1) What are the main types of radioactive decay? Give names and symbols. 1) alpha decay: 42He or 42 2)
beta decay: 0-1e or 0-1 3) gamma decay: 00
2) What are the three daughter nuclides if U-238 undergoes a. an  decay b. a  decay c. a gamma decay
234
233
233
90Th,
91Pa,
91Pa
3) Write the stepwise process of U-238 undergoing , and  decays respectively. 23490Th  42He +
233
4
229
0
229
0
229 Th
0
229
91Pa  2He +
89Ac  -1 +
90Th -1 +
90  0 +
90Th
4) How would each type of decay be deflected, if at all, in an electric field? Alpha deflects toward a negative
electric field (away from positive); beta deflects towards a positive field (away from negative); gamma
radiation is not deflected because it is not charged.
5) How does the mass number of an atom change if it undergoes a. alpha decay, mass number decreases by
four b. beta decay, mass number does not change c. gamma decay? mass number does not change
6) How does the atomic number of an atom change if it undergoes a. alpha decay, atomic number decreases
by two b. beta decay, atomic number increases by one c. gamma decay? atomic number does not
change
7) Complete the following table:
Particle
Atomic #
Relative
Relative Mass
Nuclear
Charge
Symbol
1
Proton
1
+1
1
1p
0
Electron
-1
-1
0
-1e
1
Neutron
0
0
1
0n
4
4
2
+2
4
 particle
2or 2He
0
0
-1
-1
0
 particle
-1or -1e
0
0
0
0
 ray
0
CHAPTER 5
Light and Quantized Energy
1) Light behaves light waves and particles. What else behaves like those two things? light
2) How are the energy and wavelength of light related? Inversely (the more energy, the shorter the
wavelength)
3) How are the frequency and wavelength of light related? Inversely (the higher the frequency, the shorter the
wavelength)
4) How are the energy and frequency of light related? Directly (the higher the frequency, the more energy)
5) What does it mean if energy is quantized? energy can only be gained/lost in specific/whole-number
amounts
6) The particle that holds a quantum of energy is a photon
7) What are the three possible energy states of the atom and how does the atom go between these states?
Ground (lowest energy state); excited (electron(s) in higher energy state than ground); ionized (electron
removed from atom)
8) Who predicted the spectral lines of hydrogen? Bohr Why didn’t his predictions work for other atoms?
Other atoms have more than one electron.
Electronic Structure
1) What is the aufbau principle? As an electron is added to an atom, it is filled into the lowest energy orbital
that can receive it.
2) What is Hund’s rule? As electrons are filled into degenerate orbitals (orbitals of the same energy) they
will fill so that there is the maximum number of parallel electrons before two electrons are put into the
same orbital. a.k.a. the “up up up, down down, down rule”
3) What is the Pauli Exclusion Principle? No two electrons have the same set of four quantum numbers (i.e. if
two electrons are in the same orbital, they must have opposite spins)
4) Why do electrons follow these three rules/principles? Electrons follow these rules/principles in order to
exist in a more stable (i.e. lower energy) state.
5) What are the four different orbital types we’ve learned about? s, p, d, f
6) At what energy level do s-orbitals start filling? 1 How many s-orbitals are there at each of these levels? 1
How many electrons are held by each s- orbital? 2 How many total electrons are held by s-orbitals at each
level? 2
7) At what energy level do p-orbitals start filling? 2 How many p-orbitals are there at each of these levels? 3
How many electrons are held by each p-orbital? 2 How many total electrons are held by p-orbitals at each
level? 6
8) At what energy level do d-orbitals start filling? 3 How many d-orbitals are there at each of these levels? 5
How many electrons are held by each d-orbital? 2 How many total electrons are held by d-orbitals at each
level? 10
9) At what energy level do f-orbitals start filling? 4 How many f-orbitals are there at each of these levels? 7
How many electrons are held by each f-orbital? 2 How many total electrons are held by f-orbitals at each
level? 14
10) What’s the Heisenberg uncertainty principle? We cannot know both the location and the momentum of
the electron. (i.e. We don’t know the path of the electron.)
11) Write the electron configuration and the orbital notation for each of the following elements:
ELECTRON CONFIGURATION:
Ar 1s22s22p63s23p6 or [Ne]3s23p6 ,
C 1s22s22p2 or [He]2s22p2 ,
Ti 1s22s22p63s23p64s23d2 or [Ar] 4s23d2 ,
Zn 1s22s22p63s23p64s23d10 or [Ar] 4s23d10,
Li 1s22s1 or [He] 2s1,
Si 1s22s22p63s23p2 or [Ne] 3s23p2,
K 1s22s22p63s23p64s1 or [Ar] 4s1,
W1s22s22p63s23p64s23d104p65s24d105p66s24f145d4 or [Xe] 6s24f145d4,
Rn 1s22s22p63s23p64s23d104p65s24d105p66s24f145d46p6 or [Xe] 6s24f145d46p6,
Sn 1s22s22p63s23p64s23d104p65s24d105p2 or [Kr] 5s24d105p2
ORBITAL NOTATION:
Ar 1s22s22p63s23p↑↓ ↑↓ ↑↓ or [Ne]3s23p ↑↓ ↑↓ ↑↓ ,
C 1s22s22p↑ ↑
or [He]2s22p↑ ↑
,
Ti 1s22s22p63s23p64s23d ↑ ↑
or [Ar] 4s23d↑ ↑
,
Zn 1s22s22p63s23p64s23d↑↓ ↑↓ ↑↓ ↑↓ ↑↓ or [Ar] 4s23d↑↓ ↑↓ ↑↓ ↑↓ ↑↓,
Li 1s22s ↑ or [He] 2s ↑,
Si 1s22s22p63s23p↑ ↑
or [Ne] 3s23p↑ ↑
,
2 2 6 2
6
K 1s 2s 2p 3s 3p 4s↑ or [Ar] 4s↑ ,
W1s22s22p63s23p64s23d104p65s24d105p66s24f145d ↑ ↑ ↑ ↑
or [Xe] 6s24f145d ↑ ↑ ↑ ↑ ,
Rn 1s22s22p63s23p64s23d104p65s24d105p66s24f145d46p↑↓ ↑↓ ↑↓ or [Xe] 6s24f145d46p↑↓ ↑↓ ↑↓,
Sn 1s22s22p63s23p64s23d104p65s24d105p↑ ↑
or [Kr] 5s24d105p↑ ↑
12) Which of the elements in (11) have the same outer electron configuration? Ar and Rn; Li and K; Si and
Sn
13) Using the above elements complete the following table:
Highest
Highest
Number of
occupied energy
# valence
# core
Element
occupied
unpaired
orbital
electrons
electrons
energy level
electrons
(sublevel)
Ar
3
3p
0
8
10
C
2
2p
2
4
2
Ti
4
3d
2
2
20
Zn
4
3d
0
2
28
Li
2
2s
1
1
2
Si
3
3p
2
4
10
K
4
4s
1
1
18
W
6
5d
4
2
72
Rn
6
6p
0
8
78
Sn
5
5p
2
4
46