100thIdiot wrote:Can anyone recommend any good, easy to digest, books on the elements? My brain seems to reject my attempts to understand what makes one element different to another, different to an isotope. The knowledge wont go in and the understanding wont come out.

It is actually really simple.
All atoms are made up of protons (with a positive charge), electrons (with a negative charge) and neutrons (with no charge at all). The nucleus consists only of protons and neutrons and therefore has only a positive charge. The electrons are located in the shell, which therefore has only a negative charge, which is why an atom on it's own has a neutral charge.
Now, the only difference between elements lies in the number of protons in the nucleus. Hydrogen has one proton in the nucleus, Helium two, Lithium three, and so forth. (Which also means that there are also one, two, three electrons in the shell.)
Isotopes, on the other hand, are the same element (meaning that the number of protons in the nucleus remains constant) but with changing numbers of neutrons in the nucleus.

This is - of course - the simplest possible version and while it is quite enough for the most time, it leaves many questions unanswered. For further details I'd recommend you a pretty good book, if only I could remember the friggin' title. I'll get back to you once my brain starts working again.

Mazille wrote:

100thIdiot wrote:Can anyone recommend any good, easy to digest, books on the elements? My brain seems to reject my attempts to understand what makes one element different to another, different to an isotope. The knowledge wont go in and the understanding wont come out.

It is actually really simple.
All atoms are made up of protons (with a positive charge), electrons (with a negative charge) and neutrons (with no charge at all). The nucleus consists only of protons and neutrons and therefore has only a positive charge. The electrons are located in the shell, which therefore has only a negative charge, which is why an atom on it's own has a neutral charge.
Now, the only difference between elements lies in the number of protons in the nucleus. Hydrogen has one proton in the nucleus, Helium two, Lithium three, and so forth. (Which also means that there are also one, two, three electrons in the shell.)
Isotopes, on the other hand, are the same element (meaning that the number of protons in the nucleus remains constant) but with changing numbers of neutrons in the nucleus.

This is - of course - the simplest possible version and while it is quite enough for the most time, it leaves many questions unanswered. For further details I'd recommend you a pretty good book, if only I could remember the friggin' title. I'll get back to you once my brain starts working again.

OK cool, so the thing that differentiates one element from another is the number of protons only. And an isotope of an element is determined by how many neutrons are in the nucleus. And finally there are always the same number of electrons as there are protons. So hydrogen for example has 1 proton and 1 electron? It cant just be a proton on its own, or a proton and a neutron?

Also, whats going on with electron shells? I'm looking at aperiodic table here and element 72 to element 79 look weird in the 5th and 6th shells. Why are electrons being added to the 5th shell and not the 6th until 78...

If you do remember that book, please post up. I have a few pieces of the puzzle, but I cant yet see the big picture. Thanks.

Also while we're on the subject, I've seen a few of the Youtube videos from Nottingham Uni on the elements and they talk about islands of stability in some of the videos... it might have been Ununquadium. Do we have any idea if these islands of stability could continue on indefinitely? Even in theory?

100thIdiot wrote:
OK cool, so the thing that differentiates one element from another is the number of protons only.

Basically, yes.

And an isotope of an element is determined by how many neutrons are in the nucleus.

Exactly. If you take Hydrogen, for example, which is the "most simple" element, you'll find that it only has one proton in the nucleus and one electron in the shell. One isotope of Hydrogen, however, is Deuterium, which consists of one proton, one electron, and one neutron. (Which basically makes it twice as heavy as a regular Hydrogen atom, since neutrons and protons are about the same mass and electrons are basically negligible in that regard.) Tritium, on the other hand, is another isotope of Hydrogen, which consists of one proton, one electron and - you guessed it - two neutrons.

And finally there are always the same number of electrons as there are protons.

Unless we are dealing with ions, yes.

So hydrogen for example has 1 proton and 1 electron?

Exactly, if you don't count the isotopes mentioned above.

It cant just be a proton on its own, or a proton and a neutron?

If you only have the proton, you have an Hydrogen-ion. See the link above.

Also, whats going on with electron shells? I'm looking at aperiodic table here and element 72 to element 79 look weird in the 5th and 6th shells. Why are electrons being added to the 5th shell and not the 6th until 78...

Good question. However, since I'm at my sixth beer right now, I'd ask you to wait for an answer a bit longer. I am, quite frankly, not in the proper state of mind to give a coherent answer to that.

If you do remember that book, please post up. I have a few pieces of the puzzle, but I cant yet see the big picture. Thanks.

I'll try to, but I can't guarantee a thing.

Also, do note that I am doing this in a simplified way here. I could go deeper, but I guess it's better to do the first things first. Actually, one could go a lot deeper, but since I'm merely a humble student of biology, I'm not even capable of going all the way.
Anyway, I hope I could help.

100thIdiot wrote:Also while we're on the subject, I've seen a few of the Youtube videos from Nottingham Uni on the elements and they talk about islands of stability in some of the videos... it might have been Ununquadium. Do we have any idea if these islands of stability could continue on indefinitely? Even in theory?

No idea. This is where my shallow knowledge ends, I guess. I'd forward you to wikipedia at this point, but I guess you've already been there.

100thIdiot wrote:OK cool, so the thing that differentiates one element from another is the number of protons only. And an isotope of an element is determined by how many neutrons are in the nucleus. And finally there are always the same number of electrons as there are protons. So hydrogen for example has 1 proton and 1 electron? It cant just be a proton on its own, or a proton and a neutron?

Anything called an atom is neutral by definition, and therefore has an equal number of protons and electrons. Removing or adding electrons creates ions, which always have a positive or negative charge.

Also, whats going on with electron shells? I'm looking at aperiodic table here and element 72 to element 79 look weird in the 5th and 6th shells. Why are electrons being added to the 5th shell and not the 6th until 78...

Electron shells represent areas of probability, regions which are the smallest units of electron localization; Heisenberg's uncertainty principle prevents pinpointing electron locations to any greater degree. The shell paradigm is something of a holdover from the Bohr atom model, when electrons were thought to physically exist as point particles rather than as probability states. The modern atom model is quantum-based, wherein electrons are organized according to the amount of energy required to maintain their positions relative to the nucleus (it's a bit more complicated with the repulsive interactions between electrons, but that's the general idea).

The upshot of all this is that when the shell model and the quantum model were merged, shells and energy levels did not correspond precisely. Shells (which are represented spatially) and quantum levels (which deal with energy) correspond roughly but not exactly, and these differences become more pronounced as the size of the atom increases. What you get is something like this:

... where placing energy on the vertical axis arranges the shells out of order.

Cheers, mate.
Saved me the typing.

klazmon wrote:

Alnilam wrote:Good. I think I shall start a small line of small ignorant nutshell science books

I would have thought a spectral class B0 supergiant would already know all that stuff

Your mother is so fat she has a place on the Hertzsprung-Russell diagram

Rumraket wrote:

klazmon wrote:

Alnilam wrote:Good. I think I shall start a small line of small ignorant nutshell science books

I would have thought a spectral class B0 supergiant would already know all that stuff

Your mother is so fat she has a place on the Hertzsprung-Russell diagram

Oi, can I have that for my sig?

Mazille wrote:

Rumraket wrote:

klazmon wrote:

Alnilam wrote:Good. I think I shall start a small line of small ignorant nutshell science books

I would have thought a spectral class B0 supergiant would already know all that stuff

Your mother is so fat she has a place on the Hertzsprung-Russell diagram

Oi, can I have that for my sig?

Haha, be my guest