Ideas from 'The Periodic Table' by Eric R. Scerri [2007], by Theme Structure

[found in 'The Periodic Table' by Scerri,Eric R. [OUP 2007,978-0-19-530573-9]].

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14. Science / A. Basis of Science / 4. Prediction
If a theory can be fudged, so can observations
                        Full Idea: A theorist may have designed his theory to fit the facts, but is it not equally possible for observers to be influenced by a theory in their report of experimental facts?
                        From: Eric R. Scerri (The Periodic Table [2007], 05 'Power')
                        A reaction: This is in reply to Lipton's claim that prediction is better than accommodation because of the 'fudging' problem. The reply is that you might fudge to achieve a prediction. If it was correct, that wouldn't avoid the charge of fudging.
14. Science / B. Scientific Theories / 4. Paradigm
The periodic system is the big counterexample to Kuhn's theory of revolutionary science
                        Full Idea: The history of the periodic system appears to be the supreme counterexample to Kuhn's thesis, whereby scientific developments proceed in a sudden, revolutionary fashion.
                        From: Eric R. Scerri (The Periodic Table [2007], 03 'Rapid')
                        A reaction: What is lovely about the periodic table is that it seems so wonderfully right, and hence no revolution has ever been needed. The big theories of physics and cosmology are much more precarious.
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
Scientists eventually seek underlying explanations for every pattern
                        Full Idea: Whenever scientists are presented with a useful pattern or system of classification, it is only a matter of time before the begin to ask whether there may be some underlying explanation for the pattern.
                        From: Eric R. Scerri (The Periodic Table [2007], Intro 'Evol')
                        A reaction: Music to my ears, against the idea that the sole aim of science is accurately describe the patterns.
14. Science / D. Explanation / 3. Best Explanation / a. Best explanation
The periodic table suggests accommodation to facts rates above prediction
                        Full Idea: Rather than proving the value of prediction, the development and acceptance of the periodic table may give us a powerful illustration of the importance of accommodation, that is, the ability of a new scientific theory to explain already known facts.
                        From: Eric R. Scerri (The Periodic Table [2007], 05 'Intro')
                        A reaction: The original table made famous predictions, but also just as many wrong ones (Scerri:143), and Scerri thinks this aspect has been overrated.
26. Natural Theory / B. Natural Kinds / 1. Natural Kinds
Natural kinds are what are differentiated by nature, and not just by us
                        Full Idea: Natural kinds are realistic scientific entities that are differentiated by nature itself rather than by our human attempts at classification.
                        From: Eric R. Scerri (The Periodic Table [2007], Intro 'Evol')
If elements are natural kinds, might the groups of the periodic table also be natural kinds?
                        Full Idea: Elements defined by their atomic numbers are frequently assumed to represent 'natural kinds' in chemistry. ...The question arises as to whether groups of elements appearing in the periodic table might also represent natural kinds.
                        From: Eric R. Scerri (The Periodic Table [2007], 10 'Elements')
                        A reaction: Scerri says the distinction is not as sharp as that between the elements. As a realist, he believes there is 'one ideal periodic classification', which would then make the periods into kinds.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
The colour of gold is best explained by relativistic effects due to fast-moving inner-shell electrons
                        Full Idea: Many seemingly mundane properties of elements such as the characteristic color of gold ....can best be explained by relativistic effects due to fast-moving inner-shell electrons.
                        From: Eric R. Scerri (The Periodic Table [2007], 01 'Under')
                        A reaction: John Locke - I wish you were reading this! That we could work out the hidden facts of gold, and thereby explain and predict the surface properties we experience, is exactly what Locke thought to be forever impossible.
27. Natural Reality / B. Modern Physics / 4. Standard Model / a. Concept of matter
If all elements are multiples of one (of hydrogen), that suggests once again that matter is unified
                        Full Idea: The work of Moseley and others rehabilitated Prout's hypothesis that all elements were composites of hydrogen, being exact multiples of 1. ..This revitalized some philososophical notions of the unity of all matter, criticised by Mendeleev and others.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Philos')
The stability of nuclei can be estimated through their binding energy
                        Full Idea: The stability of nuclei can be estimated through their binding energy, a quantity given by the difference between their masses and the masses of their constituent particles.
                        From: Eric R. Scerri (The Periodic Table [2007], 10 'Stabil')
27. Natural Reality / F. Chemistry / 1. Chemistry
The electron is the main source of chemical properties
                        Full Idea: It is the electron that is mainly responsible for the chemical properties of the elements.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Intro')
Periodicity and bonding are the two big ideas in chemistry
                        Full Idea: The two big ideas in chemistry are chemical periodicity and chemical bonding, and they are deeply interconnected.
                        From: Eric R. Scerri (The Periodic Table [2007], Intro 'Per')
Chemistry does not work from general principles, but by careful induction from large amounts of data
                        Full Idea: Unlike in physics, chemical reasoning does not generally proceed unambiguously from general principles. It is a more inductive science in which large amounts of observational data must be carefully weighed.
                        From: Eric R. Scerri (The Periodic Table [2007], 05 'Mendel')
                        A reaction: This is why essentialist thinking was important for Mendeleev, because it kept his focus on the core facts beneath the messy and incomplete data.
A big chemistry idea is that covalent bonds are shared electrons, not transfer of electrons
                        Full Idea: One of the most influential ideas in modern chemistry is of a covalent bond as a shared pair of electrons (not as transfer of electrons and the formation of ionic bonds).
                        From: Eric R. Scerri (The Periodic Table [2007], 08 'Intro')
                        A reaction: Gilbert Newton Lewis was responsible for this.
Does radioactivity show that only physics can explain chemistry?
                        Full Idea: Some authors believe that the interpretation of the properties of the elements passed from chemistry to physics as a result of the discovery of radioactivity. ...I believe this view to be overly reductionist.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Radio')
                        A reaction: It is all a matter of the explanations, and how far down they have to go. If most non-radiocative chemistry doesn't need to mention the physics, then chemistry is largely autonomous.
How can poisonous elements survive in the nutritious compound they compose?
                        Full Idea: A central mystery of chemistry is how the elements survive in the compounds they form. For example, how can poisonous grey metal sodium combine with green poisonous gas chlorine, to make salt, which is non-poisonous and essential for life?
                        From: Eric R. Scerri (The Periodic Table [2007], Intro 'Elem')
                        A reaction: A very nice question which had never occurred to me. If our digestive system pulled the sodium apart from the chlorine, we would die.
27. Natural Reality / F. Chemistry / 2. Modern Elements
It is now thought that all the elements have literally evolved from hydrogen
                        Full Idea: The elements are now believed to have literally evolved from hydrogen by various mechanisms.
                        From: Eric R. Scerri (The Periodic Table [2007], 10 'Evol)
19th C views said elements survived abstractly in compounds, but also as 'material ingredients'
                        Full Idea: In the 19th century abstract elements were believed to be permanent and responsible for observed properties in compounds, but (departing from Aristotle) they were also 'material ingredients', thus linking the metaphysical and material realm.
                        From: Eric R. Scerri (The Periodic Table [2007], 04 'Nature')
                        A reaction: I'm not sure I can make sense of this gulf between the metaphysical and the material realm, so this was an account heading for disaster.
27. Natural Reality / F. Chemistry / 3. Periodic Table
Moseley, using X-rays, showed that atomic number ordered better than atomic weight
                        Full Idea: By using X-rays, Henry Moseley later discovered that a better ordering principle for the periodic system is atomic numbers rather than atomic weight, by subjecting many different elements to bombardment.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Intro')
                        A reaction: Moseley was killed in the First World War at the age of 26. It is interesting that they more or less worked out the whole table, before they discovered the best principle on which to found it.
Some suggested basing the new periodic table on isotopes, not elements
                        Full Idea: Some chemists even suggested that the periodic table would have to be abandoned in favor of a classification system that included a separate place for every single isotope.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Intro')
                        A reaction: The extreme case is tin, which has 21 isotopes, so is tin a fundamental, or is each of the isotopes a fundamental? Does there have to be a right answer to that? All tin isotopes basically react in the same way, so we stick with the elements table.
Elements are placed in the table by the number of positive charges - the atomic number
                        Full Idea: The serial number of an element in the periodic table, its atomic number, corresponds to the number of positive charges in the atom.
                        From: Eric R. Scerri (The Periodic Table [2007], 07 'Models')
                        A reaction: Note that this is a feature of the nucleus, despite that fact that the electrons decide the chemical properties. A nice model for Locke's views on essentialism.
Pauli explained the electron shells, but not the lengths of the periods in the table
                        Full Idea: Pauli explained the maximum number of electrons successive shells can accommodate, ...but it does not explain the lengths of the periods, which is the really crucial property of the periodic table.
                        From: Eric R. Scerri (The Periodic Table [2007], 07 'Pauli')
                        A reaction: Paulis' Exclusion Principle says no two electrons in an atom can have the same set of four quantum numbers. He added 'spin' as a fourth number. It means 'electrons cannot be distinguished' (243). Scerri says the big problem is still not fully explained.
Elements in the table are grouped by having the same number of outer-shell electrons
                        Full Idea: The modern notion is that atoms fall into the same group of the periodic table if they possess the same numbers of outer-shell electrons.
                        From: Eric R. Scerri (The Periodic Table [2007], 07 'Quantum')
                        A reaction: Scerri goes on to raise questions about this, on p.242. By this principle helium should be an alkaline earth element, but it isn't.
Orthodoxy says the periodic table is explained by quantum mechanics
                        Full Idea: The prevailing reductionist climate implies that quantum mechanics inevitably provides a more fundamental explanation for the periodic system.
                        From: Eric R. Scerri (The Periodic Table [2007], 08 'Concl')
                        A reaction: Scerri has argued that chemists did much better than physicists in working out how the outer electron shells of atoms worked, by induction from data, rather than inference from basic principles.
To explain the table, quantum mechanics still needs to explain order of shell filling
                        Full Idea: The order of shell filling has not yet been deduced from first principles, and this issue cannot be avoided if one is to really ask whether quantum mechanics explains the periodic system in a fundamental manner.
                        From: Eric R. Scerri (The Periodic Table [2007], 09 'From')
Since 99.96% of the universe is hydrogen and helium, the periodic table hardly matters
                        Full Idea: All the elements other than hydrogen and helium make up just 0.04% of the universe. Seen from this perspective, the periodic table appears to rather insignificant.
                        From: Eric R. Scerri (The Periodic Table [2007], 10 'Astro')
The best classification needs the deepest and most general principles of the atoms
                        Full Idea: An optimal classification can be obtained by identifying the deepest and most general principles that govern the atoms of the elements.
                        From: Eric R. Scerri (The Periodic Table [2007], 10 'Continuum')
                        A reaction: He adds (p.286) that the best system will add the 'greatest degree of regularity' to these best principles.
Elements were ordered by equivalent weight; later by atomic weight; finally by atomic number
                        Full Idea: Historically, the ordering of elements across periods was determined by equivalent weight, then later by atomic weight, and eventually by atomic number.
                        From: Eric R. Scerri (The Periodic Table [2007], 01 'React')
                        A reaction: So they used to be ordered by quantities (measured by real numbers), but eventually were ordered by unit items (counted by natural numbers). There need to be distinct protons (unified) to be counted.
Moseley showed the elements progress in units, and thereby clearly identified the gaps
                        Full Idea: Moseley's work showed that the successive elements in the periodic table have an atomic number greater by one unit. The gaps could then be identified definitively, as 43, 61, 72, 75, 85, 87, and 91.
                        From: Eric R. Scerri (The Periodic Table [2007], 06 'Henry')
                        A reaction: [compressed]