# most dense object?

Discussion in 'General Science & Technology' started by hiimwayne, Dec 12, 2002.

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1. ### Chathabig brown was screwed upRegistered Senior Member

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I'm confused with all this advanced terms. But I think Osmium's nuclues has to be the densest. That is if we don't include electrons since their mass is negligible. Bohr's radius is also negligible because the nuclues will always occupy the space it wants(that is if at all it does). But we know that certain nucleus weight more than some. We have 3 yr old kids, 17 yr old kids, and 35 yr old adults, and regardless of their space they weigh different mass. The best way to determine density is to calibrate the mass, the bigger the mass the better, which is why osmium's nucleus should be the most dense. Assuming all elements have a nucleus, and all nucleus vary in size and space. Let me know if there is anythng wrong with my assertion

3. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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Now you are thinking clearly. Read my posts. But most Hydrogen does not have any neutron; however all three types have an electron.

5. ### Chathabig brown was screwed upRegistered Senior Member

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I am confused with the underlined statement. I thought the electrons determine the number of orbitals, charges determine the spin, and the electron itself is determined by the nucleus.

7. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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No. Not quite right. We now understand completely the periodic table. Basically no two electrons can be in the same quantum state.* All have an intrinsic spin (up or down) so every quantum state with "quantum numbers" can hold two. These states are distinguished by their quantum numbers. (It has been a long time so I make make some erros, but you will get the idea.)

Most important number is "n" = 1,2,3, ... and is the Shell index or crudely distance from the nucleus, (but not on any linear scale) with n=1 being the lowest energy level and closest to the nucleus.

Then the electon's angular momentum usually called "L" which is also quantized. (Actually lower case "l" is used, but that looks too much like 1 so I am using capital L here.) L can take values 0,1,2,3... but must also satisfy L < n. so for the first shell, with n= 1 only L = 0 is allowed.

Thus H has its electron in the n =1 & L = 0 and He does have two of these electrons and then the n = 1 shell is full. (I am only speaking of the "ground state" - if the hydrogen is "excited," then any n is possible.) Lithium has 3 elecrons, these same two in the n = 1 shell and the third must go in the n =2 shell but now there are two possible values of L (0 & 1) and they differ slightly in energy, especially in a magnetic field.

To fill the n = 2 shell, you need two of the l = 0 electrons (one up other down) so this is the 4 electron atom, Breylium (I think). It has the same outer shell as He, but entirely different chemisty as the n =2 shell is not yet full.

Now I must tell a about a third way electons can be different, i.e. still another quantum number, usually called "m" which can take both + and - values but |m|= or < L is required so the atom with 5 electrons has the new one in the n =2, L = 1 and m = -1, 0 or 1 state. (these state do not differ in energy except when in a magnetic field, but there always is a very weak one from the magnetic moment of the nucleus if that is not zero.) Same is true for atoms 6,7, 8, 9 and 10. Then this n = 2 shell is full and you have Neon.

I will not write all down these first 10 electron configurations (their quantum numbers) but note that I have already explained the first four. Here is 3 or half (say for spin up) of the remaining 6:
All 6 have n=2 and L= 1:
one is with m =-1
another is with m = 0
and the third has m = 1

Now after neon you must put the next electron in the n =3 shell. I will leave it as an exercise to you to complete this shell up to the next "noble gas" or "closed shell" or argon. hint there are 8 possibilities for n=3 that all are unique in their other quantum numbers (when up and down) are included or four more ways consistent with the rules of the game to make sure that at least L or m are not both the same for the n= 3 shell.

At the n= 4 shell m = -2 thru m = 2 are also for possible while L=3 and remember L may be 2, 1 or zero also I think this gives 18 different and unique psoosibilities, for the n = 4 shell (and of course you still have the 18 inner (n =3 or less) posibilities so the next noble gas, Kripton, has 36 electons and of course it nucleus has 36 protons plus a a few more neutrons as all these protons repelling each other need more neutrons so the "strong force" can hold them to gether.

After that is gets too complex for you to work out. Before the n= 5 shell is "really" full, some of the n = 6 L=0 states are actually lower in energy and your next electrons to add go there, instead of finishing then= 5 level. Later as you again begin to stuff electrons into n=5 or "inner shells" and leave the outter most shells unchanged, you get a whole series of elements with essentially the same chemisty. - Thus these are hard to separate chemically and (i think) are ,called the "rare Earth series"

as I said, I probably have made some mistakes, but that is the basic story of how nature builds up the periodic table, why noble gasses all have low chemical activity (they are the "closed shells" - will not give or accept an electron easily) etc.

These shells and configurations are sometimes called the "electron orbitals" sort as if they were orbiting the nucleus.

The L values 0,1, &2, are sometimes (for historical reasons - spectroscopic data designations before any of this was understood) called S, P, & D. regardless of their states "n values." (but of course the D ones only exist if n = 3 or greater. etc.)

To more directly answer your question (but now without just saying "that is the way it is" as I have explained why):
The size of all atoms is set by the outer most shell which has any electrons in it, and the number of electrons in it (especially wrt how many have just populated it or how many it just lacks from a "closed shell") force the chemistry to be similar. For example, all of the atoms with missing only one electron from forming a closed shell are very strong acceptors of that missing electron (Chemist call them "oxidizers" - Florine is the strongest) Oxygen is also and "oxidizer" but not as strong as Florine as it lacks two to complete that shell.

I hope this at least gives the idea. Explaining at least the first half of the periodic table is a simple part of quantum mechanics all can understand, but you will need to accept the rules about how the quantum numbers are limited instead of derive them, as can be done with a deeper understanding.
---------------------------
*This is called the "Pauli exclusion principle" and comes from the math of quantum physics. (It is true for all "Fermions" or spin = 1/2 particles not jst electrons, but they are the most important, or at least the common, ones.)

Last edited by a moderator: Jan 4, 2007
8. ### CANGASRegistered Senior Member

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You are on the right trail. Do a little more research on the established and accepted sizes of nuclei related to their observed mass.

9. ### draqonBannedBanned

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diamond on Earth. Black hole....in Universe

10. ### CANGASRegistered Senior Member

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Diamond is well proven to be true.

But expensive diamond is not even as dense as cheap lead.

Black hole is still able to be argued.

11. ### Chathabig brown was screwed upRegistered Senior Member

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CANGAS,

You said the size of an atom is determined by the outermost shell, true. But I would think that the size of a nucleus is determined by the inner most shell right? At least for the sake of finding the densest nucleus; at the very least its another way of determining the density of atoms.

12. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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Very, very wrong. Following may not be exactly correct but imagine a scale model of an atom. Where the inner most electron orbit shell is a circular path just large enough to be going around BOTH the goal posts of a US football field. Then the nucleus is something between a grapefruit or golf ball sitting on the center of the 50 yard line! All matter is mostly nothing!

13. ### Farsight

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LOL Billy, I can do better than that:

All matter is entirely nothing!

Seriously though, get two magnets, hold one in each hand and turn the poles over until you get them repulsing. Close your eyes. Feel that kind of soft shape in there. That's the sort of stuff matter is made out of, minus the magnets. Basically it's stressed space. And as to whether it's something or nothing, well, that gets a little tricky.

14. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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I know nothng about it, but think what you are saying is not far from "string theory" with its 10 or 11 "dimentions" and only 3 being big - the others being matter stuck (or "collapsed") in these three.

15. ### Chathabig brown was screwed upRegistered Senior Member

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Diamonds are the hardest natural material known to man, not the most dense. There is a difference between hardness and density. Hardness is the ability of a substance to keep its original structure, density is the amount of mass squeezed in a given space. Diamonds are the hardest natural materials because of its crystal structure. It's crystal structure has to be very good or "perfect" to be the hardest natural structure known to man. Its like having a house that can never be bulldozed, for that to happen you have to have a foundation and physical structure that's just plain top notch engineering.

You are now dabbling into QM, i'm just a first year student. I understand how you can narrate all matter as 99% space, I read a similar book on QM by Gerald Schroeder on this topic. matter is 99% space because of the distance of the atomic meta-particles, I kinda get that...right?

Last edited: Jan 4, 2007
16. ### FacialValued Senior Member

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Osmium, iridium, or osmiridium? For normal substances. I think osmium's really the densest according to its measured density and bulk modulus, and that perhaps there is something to the crystal structure of iridium that is unknown. I have sources saying iridium is 22.4, and not 22.65 - the latter seems to be a theoretical value in Wikipedia.

17. ### Farsight

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I've got some tungsten in the garage, well I think it's tungsten, it's the taps from my tap and die set. Nice and dark and heavy. Pick one up and it really weighs in your hand.

Farsight thinks... must get me some Osmium!

http://www.theodoregray.com/PeriodicTable/Elements/076/index.s7.html

I was just googling this and it said Osmium's heavier but Iridium is technically denser in terms of space lattice packing. Hmmn.

18. ### FacialValued Senior Member

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The density of elements seems to be a periodic trend -

One can see in the 4th period, the Co-Ni-Cu stretch with similar density values of 8.90, 8.91, and 8.96, respectively.

On the 5th, there is the Ru-Rh stretch w/ values 12.45 and 12.41, respectively.

Then there is the Os-Ir stretch - 22.61 and 22.65 ?

19. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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This is true because at least two massive (compared to electrons) particles (one always a proton) are added to the nucleus as the atomic number increases but the size of the atom is hardly changing with in any row of the table. Why there are rows, how many elements in each is explained in my post 164. Understanding the structure of the periodic table is one small part of quantum mechanics most can follow. After accepting the rules as to how the electron quantum numbers, n, L, & m are limited (plus two in each unique set as electron with "spin up" is not in same state as one with "spin down" even if both have he same "n" "L" & "m.")

20. ### Crunchy CatF-in' *meow* baby!!!Valued Senior Member

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cool skill (aka: lixluke)

21. ### draqonBannedBanned

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Last edited: Jun 26, 2008
22. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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I do not think there is any sense to your first sentence (about pre big bang density.), but yes there is an argument for the greatest density being when matter condensed out of the "energy soup." I suspect that there was a denser "strange" ("quark soup") stage prior to any baryons being formed, but this is way out of my field of knowledge and I do not search well for the latest POV.

I know so little about all this that I would not be surprised to learn that the average density at all stages of the very early universe were less dense than lead is today or at least the density man can and has made with high explosives very carefully exploded around some highly enriched uranium. I say this, in ignorance, as it was very hot back then and "inflation" was very rapidly increasing the volume of the universe.

Man's A-bombs surely do not hold the density record. If no stage of the early uiverse does either, (and we rule out the black holes as "cheaters") then my money is on the neutron stars.

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23. ### WaffleMasterRegistered Member

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iridium

iridium is the most confirmed material.