| 17399 | Elements don't survive in compounds, but the 'substance' of the element does [Mendeleev] |
| Full Idea: Neither mercury as a metal nor oxygen as a gas is contained in mercury oxide; it only contains the substance of the elements, just as steam only contains the substance of ice. | |
| From: Dmitri Mendeleev (The Principles of Chemistry [1870], I:23), quoted by Eric R. Scerri - The Periodic Table 04 'Nature' | |
| A reaction: [1889 edn] Scerri glosses the word 'substance' as meaning essence. |
| 17559 | Is one atom a piece of gold, or is a sizable group of atoms required? [Inwagen] |
| Full Idea: A physicist once told me that of course a gold atom was a piece of gold, and a physical chemist has assured me that the smallest possible piece of gold would have to be composed of sixteen or seventeen atoms. | |
| From: Peter van Inwagen (Material Beings [1990], 01) | |
| A reaction: The issue is at what point all the properties that we normally begin to associate with gold begin to appear. One water molecule can hardly have a degree of viscosity or liquidity. |
| 7036 | The real natural properties are sparse, but there are many complex properties [Heil] |
| Full Idea: I am sympathetic to the idea that the real properties are 'sparse'; ...but if, in counting kinds of property, we include complex properties as well as simple properties, the image of sparseness evaporates. | |
| From: John Heil (From an Ontological Point of View [2003], 13.4) | |
| A reaction: This seems right to me, and invites the obvious question of which are the sparse real properties. Presumably we let the physicists tell us that, though Heil wants to include qualities like phenomenal colour, which physicists ignore. |
| 17476 | Elements survive chemical change, and are tracked to explain direction and properties [Hendry] |
| Full Idea: Elements survive chemical change, and chemical explanations track them from one composite substance to another, thereby explaining both the direction of the chemical change, and the properties of the substances they compose. | |
| From: Robin F. Hendry (Chemistry [2008], Intro) | |
| A reaction: [The 16,000th idea of this database, entered on Guy Fawkes' Day 2013] |
| 17477 | Defining elements by atomic number allowed atoms of an element to have different masses [Hendry] |
| Full Idea: In 1923 elements were defined as populations of atoms with the same nuclear charge (i.e. atomic number), allowing that atoms of the same element may have different masses. | |
| From: Robin F. Hendry (Chemistry [2008], 'Chem') | |
| A reaction: The point is that it allowed isotopes of the same element to come under one heading. This is fine for the heavier elements, but a bit dubious for the very light ones (where an isotope makes a bigger difference). |
| 17398 | 19th C views said elements survived abstractly in compounds, but also as 'material ingredients' [Scerri] |
| 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. |
| 17418 | It is now thought that all the elements have literally evolved from hydrogen [Scerri] |
| 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) |
| 21200 | An 'element' is what cannot be decomposed by chemistry [Martin,BR] |
| Full Idea: In the modern sense 'element' means a substance that cannot be decomposed by the methods of chemistry. | |
| From: Brian R. Martin (Particle Physics [2011], 01) |
| 17467 | Isotopes (such as those of hydrogen) can vary in their rates of chemical reaction [Weisberg/Needham/Hendry] |
| Full Idea: There are chemically salient differences among the isotopes, best illustrated by the three isotopes of hydrogen: protium, deuterium and tritium, which show different rates of reaction, making heavy water poisonous where ordinary water is not. | |
| From: Weisberg/Needham/Hendry (Philosophy of Chemistry [2011], 1.4) | |
| A reaction: [They cite Paul Needham 2008] The point is that the isotopes are the natural kinds, rather than the traditional elements. The view is unorthodox, but clearly makes a good point. |