Assignment 4, Practice. Fall 2008. A Materials’ Essay; Part 2
1. Introduction to Practice Assignment 4.
In this practice for assignment 4, you will find a rogue essay on “The Structure of Oxygen”,
together with my analysis of the essay, presented as feedback to the 25 grading questions. You
will also find an essay on “The Structure of Oxygen”, which is written to the best of my ability,
also with feedback. If you study the two essays, together with my feedback, you should be able
to comprehend my ideas on good scientific writing; you should also be able to obtain a good
grade on assignment 4!
2. Specification for the Structure Essay1.
The essay should provide the reader with an introduction to the structure of copper. The text,
excluding figure captions, references, etc., should be at least 200 words in length and should be
typed in Times 12-point. The essay should be drawn from at least two independent sources,
which must be cited in the text and also listed after the text. The text must include at least one
graphic (photograph, schematic drawing etc.). The figure should be accompanied by a figure
caption and the source of the figure must be acknowledged. Other details are made explicit in
Section 3.
3. The Grading Questions
A. A. Use of English (10)
1. Does the first sentence of the essay accurately introduce and/or reflect the subject matter
of the essay?
Yes (2)
No (0)
2. Is the text grammatically correct, properly punctuated and free of spelling/typographical
errors?2
Yes (0)
No (-2)
3. Is the essay free of inconsequential verbiage?
Yes (2)
No (0)
4. Is the essay free from colloquialisms3: words or phrases that are part of the vernacular?
1
My "system" is based on "Calibrated Peer ReviewTM: A Writing and Critical Thinking Instructional Tool".
(Workshop Handbook). K. M. Brand and A. A. Russell. Copywright 2001, Regents of the University of California.
2
What is grammar? What is punctuation? The following definitions, and those in similar footnotes, have been
abstracted from Webster's New World Dictionary. 2 nd College Edition. David B. Guralnik, Editor in Chief. Simon
and Shuster. New York, NY. (1982)
Grammar: "…that part of the study of language, which deals with the forms and structures of words (morphology),
with their customary arrangement in phrases and sentences (syntax)… a body of rules for speaking and writing a
given language…”
Punctuation: "…the act, practice, or system of using standardized marks in writing and printing to separate
sentences or sentence elements or to make the meaning clearer".
3
Colloquial: “1. having to do with or like conversation; conversational”
Yes (2)
No (0)
5. Is the essay free from hyperbole4, or exaggeration?
Yes (2)
No (0)
6. Is each sentence, free of non-sequiturs5, e.g., does the second part of a sentence bear a
relationship to the first part?
Yes (2)
No (0)
B. Content (10)
7. Does the essay describe the electronic structure of the material?
Yes (2)
No (0)
8. Is the nuclear structure discussed, e.g., are isotopes identified, and/or listed?
Yes (2)
No (0)
9. Does the essay define/describe the nature of the chemical bonds in the material?
Yes (2)
No (0)
10. Does the essay state whether the material is crystalline or amorphous?
Yes (2)
No (0)
11. If the material is crystalline, is the crystal structure of the material clearly stated? If the
material is amorphous, is the term “amorphous” clearly defined?
Yes (2)
No (0)
C. Organization (4)
12. Is the content presented in a logical fashion, Does one sentence flow naturally from the
one preceding?
Yes (4)
No (0)
D. Scientific Accuracy and Attribution (6)
13. Is the essay free of scientific errors?6
Yes (2)
No (-2)
4
Hyperbole: “exaggeration…”
Non sequitur: “1. Logic a conclusion or inference which does not follow from the premises…2. a remark having
no bearing on what has just been said”
6
You might reasonably object, on the grounds that you are not qualified to comment on scientific accuracy.
Whereas this might be true in an absolute sense, you are able to check that the results quoted in the source materials
are accurately reported in the essays. For the present purposes, you may assume that the results quoted in the sources
are correct: this is not always a good assumption.
5
14. Are the source materials correctly, and adequately cited in the text?
Yes (2)
No (-4)
15. Are the source materials listed appropriately, as either footnotes, or at the end of the
essay?
Yes (2)
No (-4)
16. Is the text of the essay clearly the work of the author, i.e., is it free of plagiarism7?
Yes (0)
No (-4)
E. Use of Graphics and Tabular Materials (4)
17. If graphics (figures) and/or tabular materials are used, are they referred to adequately in
the text? If neither graphics nor tabular materials are used, score a zero. The maximum
score is four points, irrespective of the number of illustrations/tables used. If graphics
and/or tabular materials are used, but are not referred to in the text, score a -2.
Yes (4)
No (-2)
18. If graphics are used, are they accompanied by figure captions? Is the source of the
graphics acknowledged? If graphics are not used, score a zero.
Yes (0)
No (-4)
19. If graphics are used, are they numbered consecutively? If graphics are not used, score a
zero.
Yes (0)
No (-2)
20. If tables are used, does a table number accompany them? If tables are not used, score a
zero.
Yes (0)
No (-2)
21. If tables are used, are they accompanied by a table heading? Is/are the source(s) of the
tabular material acknowledged? If tables are not used, score a zero.
Yes (0)
No (-4)
22. If tables are used, are the listed parameters explained, and/or defined as footnotes to the
table, or in the text? If tables are not used, score a zero.
Yes (0)
No (-4)
F. Formatting (6)
23. Is the essay formatted for ease in reading and comprehension?
Yes (2)
No (0)
7
Plagiarize: “ to take (ideas, writings, etc,) from (another) and pass them off as one’s own”
24. Is the text of the required length (200 words minimum)?8
Yes (2)
No (-2)
25. Is the text single-spaced, Times, 12 point?
Yes (2)
No (0)
MAXIMUM SCORE
G. Overall Rank
26. The Overall Ranking of the essay is given by the sum of questions 1-26
30+
20+
10+
Less than 10
8
Excellent
Good
Poor
Remedial Action Needed
Does this mean that you (the student) must determine, or estimate the word count? Yes!
40 POINTS
The Structure of Oxygen (Rogue Essay).
There is no need to make oxygen in the laboratory because it is readily available commercially or
through air liquefaction plants. In fact, oxygen is the most abundant terrestrial element. It has an
atomic number of 8, hence 8 protons and 8 neutrons. In a neutral atom, it has eight electrons
orbiting the nucleus as shown in the Figure below, which is a schematic representation of the
shell structure of oxygen – not what the atom of oxygen “looks like”. Oxygen has three naturally
occurring isotopes.
Oxygen is a gas with a monoclinic crystal structure as shown below.
Isotope
Atomic mass
(ma/u)
16
O
17
O
18
O
15.99491463
(5)
16.9991312
(4)
17.9991603
Natural
abundance
(atom %)
99.757
(16)
0.038
(1)
0.205
Nuclear spin (I)
0
Magnetic
moment
(m/mN)
0
5/2
-1.89380
0
0
(9)
(14)
Space group: C12/m1(Space group number :12)
Structure: monoclinic
Cell
a/pm b/pm c/pm
  
Parameters 540.3 342.9 508.6 90.00 132.53 90.00
Oxygen forms chemical bonds with virtually all other elements. The most famous of the oxides
is dihydrogen oxide (water) and compounds of carbon and oxygen such as carbon dioxide (CO2)
alcohols (R-OH), and aldehydes (R-CHO).
References.
[1] WebElementsTM, the periodic tale on the WWW. Mark Winter: The University of Sheffield
and WebElement Ltd., UK © Mark Winter, 1993-2008. .Accessed 07/03/08
http://www.webelements.com/webelements/elements/text/O/key.html
[2] “Oxygen”. From Wikipedia, the free encyclopedia. Licensed to the public under the GNU
Free Documentation License. Accessed 06/16/08
http://en.wikipedia.org/wiki/Oxygen
Feedback. Essay # 2.
Number Answer Feedback
1.
No
The first sentence is irrelevant to an essay that is describing
structure. It might be relevant if the essay were discussing
processing.
2.
Yes
The style is poor but the mechanics appear to be OK
3.
No
The second sentence begins with: “In fact…” The phrase “In
fact” is meaningless: either oxygen is, or is not the most abundant
terrestrial element (it is). In sentence 4, the phrase “… not what
the atom of oxygen “looks like”” is unnecessary; earlier in the
same sentence, the figure is described as a “… schematic
representation”.
4.
Yes (?) A borderline yes! The phrase “In fact…” is colloquial, and should
not be used in formal writing.
5.
Yes
6.
No
The sentence “It has an atomic number of eight, hence 8 protons
and 8 neutrons” is illogical. The atomic number cannot be used to
determine the number of neutrons. The sentence “Oxygen is a gas
with a monoclinic crystal structure…” is also a classic nonsequitur: a gas cannot be crystalline.
7.
Yes
The description is meager and barely sufficient.
8.
Yes
The last sentence of the first paragraph mentions isotopes, and a
list is provided in the table, which is not referred to in the text
9.
No
10.
No
Nowhere is it explicitly stated that oxygen is crystalline.
11.
No
It is stated that “Oxygen is a gas with a monoclinic crystal
structure…” which is a non-sequitur. A list of meaningless
parameters, such as “Space group” is also provided, but not
mentioned in the text.
12.
No
The essay begins with a statement about processing, gives some
garbled structural information and finishes by listing several
oxygen-bearing compounds.
13.
Yes
Something must be right!
14.
No
The source materials are not cited at all. Hence, the essay is
plagiaristic. The last paragraph is virtually a direct quote from ref
[2]. The figures and tables are copied directly from ref [1]
15.
Yes
16.
No
The author is guilty of plagiarism, for the reasons enumerated in
the answer to question 14.
17.
No
The figures are only alluded to using the phrase “as shown
below”. They are not numbered. The tabular material is not
referred to at all, making the information worthless.
18.
No
There are neither figure numbers, nor captions (-2). There is no
acknowledgment regarding the source of the figures (-2)
19.
No
Score
0
0
0
2
2
0
2
2
0
0
0
0
2
-4
2
-4
-2
-4
-2
20
21
No
No
22
No
23
No
24.
25
No
Yes
There are neither table numbers, nor table headings (-2). There is
no acknowledgment regarding the source of the tabular materials
(-2)
I wonder if the author knows what “nuclear spin” and “magnetic
moment” signify?
Figures, tables and text are all mixed together, making it difficult
to “navigate” through the essay.
By my count, the word total (text only) is 134
QUANTITATIVE SCORE
-2
-4
-4
0
-2
2
-14
The Structure of Oxygen.
Oxygen is in period 2, group 16 of the periodic table [1]: in its standard state at 25˚C, it is a
colorless, odorless gas. Oxygen has an atomic number of eight, which means that its nucleus
contains eight protons, and for a neutral atom, there are eight orbiting electrons. The ground state
(lowest energy) electronic structure for oxygen [1] is:
[He].2s2.2p4
which is equivalent to a shell structure of 2.6 [1].
Its atomic weight, which is approximately equal to the number of protons, plus the average
number of neutrons in the nucleus, is 15.9994 [1]. Oxygen’s three stable isotopes are
16
O(99.757%), 17O(0.0380%) and 18O(0.205%) [1].
It is not possible to define a unique atomic radius to oxygen, or indeed any element, because this
radius varies with the environment of the atom. Perhaps the most meaningful are the covalent
radius (0.73nm) and van der Waals radius (1.652nm) [1], which yield the interatomic distance
within a molecule (covalent), and the somewhat larger intermolecular distance (van der Waals).
The covalent and van der Waals radii are indicated on Figure 1a.
Figure 1. Schematic diagrams of the crystal structure of solid (crystalline) oxygen. In both cases, the
orientation of the unit cell is shown in the lower left-hand corner (adapted from ref. [1]). a). Ball and stick
representation. a). Hard-sphere model. In a), the covalent radius is shown to correspond with (half) the
interatomic spacing, within oxygen molecules. The van der Waals radius is characterized by (half) the
intermolecular spacing.
Although a gas at room temperature, if sufficiently cooled, oxygen will liquefy and finally
solidify (boiling and melting points of –182.9˚C and –218.3˚C respectively [1]). In common with
most solids, the solid form of oxygen is crystalline, where ref [2] defines a crystal as:
“… a crystal is a solid in which the constituent atoms, molecules, or ions are packed in a
regularly ordered, repeating pattern…”
Figures 1a,b are schematic drawings of the crystal structure of oxygen, which is monoclinic [1],
with unit cell parameters, a=0.5403nm, b= 0.3429nm and c=0.5086nm. As noted in [3], a crystal
structure can be described by:
“…a unique arrangement of atoms in a crystal …. a motif, a set of atoms arranged in a particular
way…”
The orientation of the unit cell is indicated in the lower left hand corner of Figures 1a,b. Note,
however, that the unit cell is not of the correct size
References.
[1] WebElementsTM, the periodic tale on the WWW. Mark Winter: The University of Sheffield
and WebElement Ltd., UK © Mark Winter, 1993-2003.
http://www.webelements.com/webelements/elements/text/O/key.html
[2] “Crystal”. From Wikipedia, the free encyclopedia. Licensed to the public under the GNU
Free Documentation License. Page last modified Aug.11, 2005.
http://en.wikipedia.org/wiki/Crystal
[3] “Crystal Structure”. From Wikipedia, the free encyclopedia. Licensed to the public under the
GNU Free Documentation License. Page last modified Aug.11, 2005.
http://en.wikipedia.org/wiki/Crystal_structure
Feedback. Essay #1.
Number Answer Feedback
1.
Yes
The first sentence introduces some structural aspects of oxygen:
it serves as a springboard for the remainder of the essay.
2.
Yes
3.
Yes
4.
Yes
5.
Yes
6.
Yes
7.
Yes
Both the “ground state” and “shell structure” of oxygen’s
electronic structure are presented (end of first paragraph).
8.
Yes
The number of protons is presented in paragraph 1, and the
stable isotopes of oxygen are listed in paragraph 2.
9.
No
10.
Yes
See second sentence of fourth paragraph “… the solid form of
oxygen is crystalline…”
11.
Yes
In the quote following the fourth paragraph, a crystal is defined,
and the fifth paragraph describes the crystal structure of solid
oxygen, which is also shown in the figures, which are referred to
in the text.
12.
Yes
The essay progresses from a description of electronic structure,
to a listing of isotopes, to a discussion of atomic radius, and
finally to crystal structure.
13.
Yes
14.
Yes/No The citation practice is generally OK. However, no citation
accompanies the second paragraph: the data are from ref. [1]
Note that I am using a numerical system with the reference
numbers being located at the end of the passage to which it
refers. Also note also that the period (full-stop) is located after
the reference, and the references are numbered sequentially.
15.
Yes
In keeping with the numerical system, the references are listed
sequentially following the text.
16.
Yes
17.
Yes
The fifth paragraph refers to, and describes the figures.
18.
Yes
Note that the first part of the caption is not a full sentence: it is a
description. The rules for figure captions are somewhat different
from normal text: figure captions should be descriptive.
19.
Yes
In this instance, there is one figure consisting of two parts, a)
and b), which are referred to in the text, and labeled on the
figures.
20
NA
21.
NA
22
NA
23
Yes
Paragraphs are delineated by leaving spaces, and the figure
caption is distinguished from the text by a change in font
Score
2
0
2
2
2
2
2
2
0
2
2
4
2
0
2
0
4
0
0
0
0
0
2
24.
25.
Yes
Yes
Word count, text only: 321
QUANTITATIVE SCORE
2
2
34