LESSON 8: DEVELOPMENT OF THE ATOMIC MODEL
Week 5
Assignment:
1)
Read textbook pages corresponding to this topic.
2)
Define the following terms:
Atom, model, law of definite composition, quantum, electron, neutron, proton, continuous spectrum, line spectrum, quantized, principal energy level, Heisenberg uncertainty principle
3)
Watch lecture and take notes.
4)
Complete review questions, and check answers.
LESSON 8 REVIEW QUESTIONS
Solutions are at the end of the video for this lesson.
(1-10) (1 pt. each) Circle the best answer.
1)
Electrons have a ______________ charge a) positive
2)
Protons have a ______________ charge a) positive
b) negative
b) negative
c) neutral
c) neutral
3)
_______________ determined that different elements have different masses. a) Dalton b)Democritus c)Rutherford d)Thomson e)Bohr
4)
___________________ discovered electrons. a) Dalton b)Democritus c)Rutherford d)Thomson e)Bohr
5)
Prior to the quantum model, the atomic model developed by ______________ was the most sophisticated
model. a) Dalton b)Democritus c)Rutherford d)Thomson e)Bohr
6)
The ______________ model is usually used to discuss light emission by atoms a)Thomson b)Bohr c)quantum
7)
The Heisenberg uncertainty principle states that it is impossible to know the energy and location of a/an
________________ as it orbits an atom a)proton
b)electron
c)neutron
8)
Atoms give off distinct ______________ spectrums. a)line b)continuous c)energy
9)
Connection to Lesson 7: The density of water is about a)1 kg/ml b)1 ml/g c) 1 g/ml d) 1 g/L
10)
Connection to Lesson 4: Energy is _____________ in an exothermic reaction. a)released b)absorbed c)increased
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Week 5
LESSON 9: ELECTRON CONFIGURATION
Assignment:
1)
Read textbook pages corresponding to this topic.
2)
Define the following terms:
Principal energy level, orbital, sublevel, Pauli exclusion principle, diagonal rule, Aufbau principle, electron configuration, orbital notation, photon, Hund’s rule, quantum number
3)
Watch lecture and take notes.
4)
Complete review questions, and check answers.
LESSON 9 REVIEW QUESTIONS
Solutions are at the end of the video for this lesson.
(1-7) (1 pt. each) Fill in the blanks using the words listed below. All words should be used and each word should
only be used one time.
Diagonal, Hund’s, notation, opposite, orbitals, principal energy levels, quantum, smaller
1)
Electrons exist in ___________, which make up sublevels, which make up
_________________________.
2)
The Aufbau principle states that the arrangement of electrons may be determined by observing their arrangement around a ___________ atom.
3)
The _____________ rule is used to determine the order of increasing energy for an atom’s
sublevels.
4)
Orbital ______________ is another way to represent the electron configuration around an
atom.
5)
The Pauli exclusion principle states that paired electrons must have _________________
spins.
6)
_________________ numbers are like addresses for electrons.
7)
_______________ rule states that when writing the orbital notation for an atom, each orbital in a sublevel gets one electron before any receive two.
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Week 5
8)
Write down the arrangement of sublevels used in the diagonal rule. 2 pts.
9)
Write the electron configuration for sodium (atomic number = 11). 2 pts.
10)
Write the electronic configuration and orbital notation for sulfur (atomic number = 16) 4 pts.
11)
Write the electron configuration for Iodine (atomic number=53) 3 pts.
12)
What atom would have an electron with a quantum number of (3,1,0,½), potassium or sodium? (2 pts.)
13)
This set of numbers, (2, 0, -1, -1/2) cannot be used to describe the location of an electron. Why not? (2 pts.)
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Week 5
Laboratory Activity
5
Electrons and Energy Levels
Introduction
“Quantum reveres you. At edicts you utter
Each tiny electron examines its plight;
Confined to his orbit, he flies in a flutter,
Rushes and radiates, estimates height,
Pre-judges the motion,
And dreams up the notionMixing up Cause and Conclusion, in frightTo leap from his mother orb,
Straight to another orb”
From the poem “Hail to Neils Bohr”, written in the 1920’s by Russian theoretical physicist Vladimir A. Fock and reprinted in The Great
Physicists from Galileo to Einstein by George Gamow.
In the early 1900’s, Neils Bohr developed his theory of atomic energy levels. It was based on ideas he gathered from
James Jeans’ experiments with radiant energy. Jeans found that radiant energy could exist only in certain minimum
amounts or multiples thereof, so Bohr applied that idea to electrons orbiting atoms. An atom’s electrons could be
thought of like a bicycle’s gear system. On a bicycle, you can ride in 1st, 2nd, 3rd gear, etc., but not in between
gears. Likewise on an atom, electrons exist in distinct energy levels around an atom, and when an atom “falls” from
a higher to a lower energy level, the lost energy is released in the form of light energy. Since the electron fell a specific, or “quantized” amount, then it gives off a specific color (or wavelength of light). Therefore, since each atom
is different with different numbers of electrons and energy levels, when energy is added, each atom will release that
energy with a unique spectrum. In Laboratory Activity 5 you will answer the question:
Do electrons exist in distinct energy levels around an atom?
Hypothesis (Introduction excerpted from The Great Physicists from Galileo to Einstein by George Gamow, p. 239-246)
Methods
Materials
Equipment: Bunsen burner, striker, spectroscope, spatula, XPlorer GLX Datalogger, Ocean Optics Spectrometer, 150 mL beaker, wooden splints
Chemicals: distilled water, chloride salts of calcium, copper, lithium, manganese, potassium,
sodium, and strontium
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Week 5
Procedure
For a detailed explanation of procedure, please watch the video lab. Record all measurements below.
CALCIUM
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
COPPER
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
LITHIUM
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
MANGANESE
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
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625-740
Week 5
POTASSIUM
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
SODIUM
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
STRONTIUM
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
Results:
UNKNOWN
380-420 420-440 440-500 500-520 520-565 565-590 590-625
wavelengths in nanometers
625-740
The unknown is one of the seven elements tested, what is it?
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625-740
Week 5
Discussion:
1. Was your hypothesis correct? Why or why not?
2. List at least three sources of error.
3. Considering the question answered in this experiment, list some similar questions
that could be answered by conducting a science experiment.
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