Is neutronium an element?

Factual Questions
1

The June 2005 issue of Discover magazine featured a small article about a “bold redesign” of the periodic table of elements. Philip Stewart of Oxford University has rearranged the table so that the groups radiate outward from a central point. According to the article, this “Chemical Galaxy” arrangement (which is superimposed over a picture of an actual galaxy) seeks to “convey chemistry’s true majesty and coherence.”

The article also happens to mention the fact that Stewart’s primary field of study is plant biology, although of course that doesn’t mean he can’t also contribute valuable insights about chemistry. In any case, he has apparently contrived to have his new, improved periodic table distributed to schools all over Great Britain. I’m frankly dubious that the traditional square-britches version is in danger of being supplanted anytime soon.

One feature of the new table did catch my attention, though; right at the center of the “Chemical Galaxy” is a lowercase “n.” The sidebar explains: “Neutronium (element zero), a bare neutron, is absent from the standard periodic table.”

Now, I freely confess to having only a rudimentary, undergraduate-level understanding of the physical sciences, which may be hopelessly out of date by now. However, I have never heard neutronium described as an element by anyone, except maybe on Star Trek. The notion of a “chemical element” that isn’t actually composed of atoms seems fundamentally illegitimate somehow.

Also, if a single neutron can be categorized as an element, then it would seem to follow that any other substance containing neutrons cannot also be an element itself-- which would leave only hydrogen and neutronium as “genuine” elements. Admittedly, this would make learning the periodic table much easier.

Color me skeptical, but I don’t entirely trust filler material from newsstand magazines to accurately represent the physical sciences. Is there any serious argument in favor of adding neutronium to the periodic table?

2

Not sure about the neutronium question, but here is a jpeg of Stewart’s chart.

3

I’m curious why he put hydrogen above carbon instead of lithium.

4

I’d always wondered about the original table.

Seemed way too complex and the patterns too perfect for a person to have created it. Intelligent design perhaps? :dubious:
I’m not sure what I think of the new one.

5

Sound like BS to me. He’s just starved for attention and hoping a controversy will provide the attention and vindication.

6

I’m not a nuclear physicist, but the concept would have to include other “bare” elementary particles like electrons and protons.

So, given that neutronium was an element, then would not electronium and and protonium also be elements?

The logic escapes me. Elements, according to what I’ve learned, are not subatomic particles, and in fact are not even atoms. Elements are a mix of subatomic particles which in some combination form atoms, which are combined in a particular way to form some…uh, substance which is considered an element.

Certainly, neutronium can, and almost certainly does, exist. And it is a massive substance. It is composed of nothing but neutrons, really squashed together. But even if we take the substance as a whole, I wonder if even this could be considered an element according to the current rules of science. On this matter, I rely on you all to educate me, since I’ve never considered this particular case, and do not have the background to properly pursue it any further.

7

First, to tackle the hydrogen-above-carbon side issue: Elements in Class I of the normal periodic table, except hydrogen, have only one electron in a shell that is capable of holding eight (s and p orbitals; never mind that it can hold more in other orbitals, as it will only do so when it is an inner shell and the outermost shell has eight or less eletrons). Hydrogen, by contrast, has merely the K shell with only an s orbital, and has one electron of a maximum capacity of two.

So it behaves in a manner that makes it often an electron donor but occasionally an electron acceptor, as in the alkali hydrides. This character is termed “amphoteric.” But the other elements which are amphoteric are, when neutral possessed of an outer shell of four electrons, able to act as donor or acceptor for four to complete their shells. They are the carbon group. So it makes as much sense to consider hydrogen, with its amphoteric character, as grouped with them, as with the alkali metals or with the halogens, both of which it sometimes resembles.

Now down to the neutronium question.

There is no really great definition of element. But one that would be functional would be that it is a quantity of matter that has the characteristic of isotropy: every part of it which is separable by purely chemical means, as opposed to atomic physics or ionization, is identical to every other part of it. For example, graphite can be broken down into carbon atoms; elemental copper, to copper atoms, etc. In contrast, water breaks down into hydrogen and oxygen atoms, methane into carbon and hydrogen atoms, etc.

But note that except for the examples, my description does not use the term “atom.” Certainly we know that the normal minimal-unit-of-element is an atom. But nothing requires that to be so. And if we attempt to describe the atom, we quickly run into problems. Typically, an atom consists of a nucleus of one or more protons and one or more neutrons around which a number of electrons revolve. However, ions may have no electrons, and the majority of matter in the universe consists of protium (light hydrogen), either ionized or not, with no neutrons. Is a naked proton a chemically valid element? Well, yes: ionized hydrogen clouds in interstellar space are largely made up of naked protons.

So we have established that there is one major case in which a lone subatomic particle can in fact be an element.

Now, what is neutronium made up of, chemically? The answer is, of course, neutronium, naked neutrons without other particles bonded to them. Does it meet the definition above? Yes; like ionized hydrogen, it is an isotropic quantity of matter that cannot be separated into different constituents. It is therefore an element, just as hydrogen is.

8

I’d say there’s no practical reason for it. The point of the periodic table (as I’m sure you know) is that elements are grouped in such a way that elements with similar configurations of valence electrons, and hence similar chemical properties, lie near each other (e.g., in the same column). But a bare neutron has no electrons, and so no chemical properties; the mechanisms of any interactions with neutronium will be completely different (probably principally non-electromagnetic) than interactions of atoms with other real atoms, and so the energy and temperature scales are likely to be completely different. It doesn’t even make much sense to group it with the noble gases, because they at least repel each other electrostatically and act like nice ideal gases with nanometer-sized spheres; neutrons act more like femtometer-sized particles.

9

I don’t think so. The essential characteristic of an element is that every atom of that element has the same structure (more or less). Every atom of carbon has six protons, every uncharged atom of carbon has six electrons. Most carbon atoms have six neutrons, but this is not a requirement. Any collection of carbon atoms arranged in any way is carbon.

10

Philip Stewart talks about neutronium.
Patrick Stewart talks about neutronium.

:dubious:

11

Yes, but we are speaking here of atoms, as you say.

We are not speaking of subatomic particles that constitute atoms.

12

Well, I’m not a real scientist, but I’m a HS chem teacher.

“Protium” is a name we call hydrogen-1, when it has no neutrons on it.

The smallest piece of an element would be an atom. You can have sheet aluminum, which would have almost uncountable numbers of Al atoms, but it’s still aluminum as you cut it apart, until you cut a proton off the neucleus, because it’s not Al unless it has 13 protons.

I’ve never heard of a lump of neutrons solely, although I haven’t heard of everything. Are you being serious with that?

Funnily enough, just today for our midterm review, I was pointing out to kids that you can’t have an element without a proton. Without a proton, you can’t attract electrons, and your lump doesn’t DO anything. (I admit that the noble gasses don’t do much, either.) AFAIK, a lump of neutrons is called “a lump of neutrons”.

13

If you breathe them, they change your voice. :smiley:

Breathing xenon changes your voice down a few octaves, but it’s not recommended. Because it’s much heavier than other gases in air, it would sit at the bottom of your lungs, basically suffocating you like being drowned.

Good thing they don’t sell xenon balloons at carnivals. :smiley:

14

The only context in which one can talk of neutronium as a substance is in a neutron star. But that’s not a neutron, that’s about 2 × 10[sup]57[/sup] neutrons. Take a smaller amount of it, and you will not have anything with properties resembling those of a neutron star. You’ll just have a big messy explosion. Furthermore, while a neutron star is composed primarily of neutrons, it’s not entirely neutrons. As much as 10% of the star’s mass is in protons, with an equal number of electrons to match. In fact, it’s the electrons, not the neutrons, which provide most of the pressure which supports the star.

On this new periodic “table”, yeah, it’s (arguably) pretty. But if I want pretty, I’m not going to go to a chemistry class. A periodic table is a tool, and this one is an awfully poor one. The elements are arranged in an inconvenient way, and so much space is wasted on the backdrop (which isn’t even a particularly good picture of a galaxy) that there’s no room for any useful information (atomic masses, density of most common form, lifespan of unstable isotopes, melting and boiling points, typical crystalline structure, and electron configuration come to mind as common information on periodic tables).

15

The spiral galaxy picture is offensive to the senses. Real spirals don’t have funny radial lines crosshatching the arms. If Stewart wants to draw a parallel between tiny atoms and great big galaxies, he should use something that looks like a galaxy, not something that looks like an uneducated fantasy. If he’s going to include a neutron at position zero, he should also include spaces for all the isotopes of each element which differ solely by neutron number.

16

But by this definition, then, is hydrogen (or any atom) an element? If subatomic particles can be considered “chemical elements,” then it seems like interactions between those particles should also count as “chemical reactions.” So both ionization and atomic physics should qualify. Surely if neutronium can be said to have a “chemical makeup” of pure neutrons, then atoms could be regarded as “chemical compounds” of elements in various fixed proportions, which can be altered by reaction with other subatomic particles/elements.

17

Ok, I accept that, but how then would you have an element composed soley of electrons, or an electron? Just asking.

On the subject of hydrogen, it consists of a proton and an electron. I have to bow out on Hydrogen-1, which you say is a single proton and nothing else. I have not heard of this, and thus can not contest it. Perhaps you could elaborate, but I am only asking for clarification on this.

18

sorry. Missed replying to something there. This was am I serious about a lump of neutron.

Yes, I was completely serious, as in regards to neutons stars, where the extreme gravity has broken the electron bonds to the point where there are nothing but neutrons in the star.

19

… the hell is this shit? The old periodic table was plenty coherent.

(No, I don’t have anything useful to contribute.)

20

A list of alternate periodic tables

http://chemlab.pc.maricopa.edu/periodic/styles.html