15 Replies Latest reply on Apr 26, 2016 12:04 AM by Donivan Porterfield

    questions on atoms

    Beth Bruce

      I am looking for a person knowledgeable in the structure of atoms; specifically the breakdown of radon and each element it breaks down into, and from. The number of protons, neutrons and electrons.  I have an email I would like to send to someone who can help me.  I perform radon testing and am making a coloring/storybook and that has led me to this.  Thank you. Beth Bruce. beth_rook@aol.com.  540-658-4663.

        • Re: questions on atoms
          Christine Brennan Schmidt

          Hi Beth,

          I don't do much chemistry anymore, but i do know there are lots of resources on the internet on Radon decay.

           

          The most common isotope of Radon is Rn-222.  A good decay scheme is available on Wikipedia.

           

          Perhaps another chemist can provide you with more information.

            • Re: questions on atoms
              Beth Bruce

              Thank you, i have researched online and am hoping to get some specific information.

                • Re: questions on atoms
                  Christine Brennan Schmidt

                  What sort of specific information are you looking for?

                    • Re: questions on atoms
                      Beth Bruce

                      Basically the breakdown of each atom in the series, the number of protons, neutrons, and electrons.  I am not a science or math person or a teacher.

                       

                      This all started because I do radon testing and now I am branching out. I am making a children's coloring book and storybook that I hope will be entertaining and educational.  Can you refer me to an expert?  I need someone to review my project when I am done.

                       

                      First, question on Beta decay-With Beta decay the neutron count goes down by 1; a neutron transforms into a proton and electron.  The resulting proton stays in the nucleus increasing the proton count by 1.  The electron is expelled;   Where does that electron go?  Does it leave the atom entirely?  Also,  do the other electrons stay with the atom still?

                       

                      Do I need to make any corrections?  So far these are my notes:

                       

                      Radon 222

                      86 protons

                      136 neutrons

                      86 electrons

                       

                      Alpha decay, emits 2 protons and 2 neutrons.

                      Becomes Polonium 218.

                       

                      Polonium 218

                      84 protons

                      134 neutrons

                      86 electrons?

                       

                      Alpha decay, emits 2 protons and 2 neutrons.

                      Becomes Lead 214.

                       

                      Lead 214

                      82 protons

                      132 neutrons

                      86 electrons?

                       

                      Beta decay, a neutron becomes a proton and electron and the electron goes way

                      Becomes Bismuth 214

                       

                      Bismuth 214

                      83 protons

                      131 neutrons

                      86 electrons?

                       

                      Beta decay, a neutron becomes a proton and electron and the electron goes away

                      Becomes Polonium 214

                       

                      Polonium 214

                      84 protons?

                      130 neutrons?

                      86 electrons?

                       

                      Alpha decay, emits 2 protons and 2 neutrons.

                      Becomes Lead 210

                       

                      Lead 210

                      82 protons

                      128 neutrons

                      86 electrons?

                       

                      Beta decay, a neutron becomes a proton and electron and the electron goes away

                      Becomes Bismuth 210

                       

                      Bismuth 210

                      83 protons

                      127 neutrons

                      86 electrons?

                       

                      Beta decay, a neutron becomes a proton and an electron and the electron goes away

                      Becomes Polonium 210

                       

                      Polonium 210

                      84 protons

                      126 neutrons

                      86 electrons?

                       

                      Alpha decay, emits 2 protons and 2 neutrons.

                      Becomes Lead 206.

                       

                      Lead 206

                      82 protons

                      124 neutrons

                      86 electrons?

                       

                      Stable, the end.

                       

                      Question on Alpha particles; they supposedly plate out; what does that mean exactly?  They hit the wall and do they disappear?

                       

                      (Makes me wonder; the Lead 206 is in the radon which is floating in the air.  Does the lead keep floating up into the atmosphere also, and if it hits a wall?)

                       

                      After this I will start over from uranium and work my way up to radon gas.

                       

                      I am noticing in science one question leads to another...

                        • Re: questions on atoms
                          Christine Brennan Schmidt

                          Hi Beth,

                          A couple things -

                          Beta emission in this case is the expulsion of an electron particle from the nucleus. 

                           

                          The electron counts you are tracking are irrelevant to the identity of the atoms being created. It is the proton and the neutron count that distinguishes one atom from another. When we talk about nuclear decay, we don't usually worry about the number of electrons around the nucleus. The number of electrons can impact its reactivity with other atoms, i.e. the chemistry it has, but when it reacts in this way, the nucleus does not change its number of protons and neutrons.  The arrangement of electrons is based on some complex mathmatical probabilities and an atom may lose or gain electrons to add stability to the electron configuration.

                           

                          I suspect that lead plates, i.e, deposits upon some surface instead of remaining in the air.

                  • Re: questions on atoms
                    Michael Dowell

                    Hi Beth,

                     

                    I agree with everything Christine said, but I think that you have a question still out there: we started with 86 electrons, so what happened to them?  Let's do it comic book style; students learn well from that. In Panel 1 we have a Rn nucleus lower left and a big cloud of gray or silver electrons everywhere else. But that nucleus is unstable! It's rippling. Maybe that looks red and green in the comics universe but the nucleus has vibrational modes in the liquid-drop model of nuclei, and maybe by Panel 3 it's separated into a 218Po84 nucleus and an alpha particle, a 4He2 nucleus, both still inside the electron cloud. They are both positively charged and they are going to repel each other, and in any case the nuclear decay gave off a lot of energy--5.6 MeV (million electron volts), and that becomes kinetic energy moving the particles away from each other. If you look it up in the nuclear decay scheme in the Chart of the Nuclides, aka Table of the Isotopes, approximately 5 MeV goes with the alpha particle. I'm imagining a panel in which the Po nucleus is still surrounded by the big electron cloud and the positively charged alpha particle is starting to move out through the cloud at 4200 km/sec (5 MeV = 1/2 mv2) and someone says (either nucleus or an observer) "Wait! What about the electrons?!"

                    • Re: questions on atoms
                      Michael Dowell

                      And then, Beth, the alpha particle says "I'm taking 2 of them! I'm a helium nucleus after all. I gain 50 eV for the first electron and 25 eV for the second (which you look up in a table of Ionization Potentials) so you are paying me energy to take them away!" The answer to your question, "86 electrons every time?" is, every time an alpha particle (helium nucleus) is emitted, it takes two electrons with it as it passes through the cloud of electrons that surrounded its former parent atom. The other daughter atom, Po in this case, now has 84 atoms, just the amount it needs to be a neutral atom. Since there is only one parent or daughter atom in any panel, we don't have to consider whether it's a gas or a solid and that should not matter.  When your atom decays by beta emission and emits an electron, the nuclear charge increases by +1. If you could capture that electron the new daughter atom would remain neutral. Certainly there is an empty space in the electron orbitals, and you would give off 5 or 10 eV if you filled the orbital; it would be energetically favorable. But the betas being emitted have more than 1 MeV of kinetic energy, they probably just keep going and leave positive ions behind. It's energetically favorable to turn any of the new positive ions in your decay chain into  neutral atoms; they just need to find an electron that has much less kinetic energy than the beta. If the ion landed on a metal or glass surface, it could probably pick up an electron. I'm glad that you asked the question the way you did-- artists always worry about important stuff.

                        • Re: questions on atoms
                          Beth Bruce

                          This is fascinating but I don't understand much of what you just said.  It sounds like you all are saying that the electrons change a lot.  So then how did radon 222 come to have 86 electrons in the first place?  I drew my radon atom with electrons in specific orbits around it.  In fact I believe I found that orbit information and it was specific.  I actually had to re-draw it because I didn't do that to begin with.  If I leave each decay product in the chain with with 86 electrons is it still correct then?  How much can these number of electrons fluctuate, like what is a range? 

                            • Re: questions on atoms
                              Beth Bruce

                              I just read again; it looks like you said when the alpha particle is emitted it takes 2 electrons with it?  So every time it's alpha I can subtract 2 electrons? 

                               

                              and for beta, these are my notes: With Beta decay the neutron count goes down by 1; a neutron transforms into a proton and electron.  The resulting proton stays in the nucleus increasing the proton count by 1.  The electron is expelled. 

                              So based on what I think  you said, that electron goes out of atom most likely?  So the number of electrons doesn't change then?

                               

                              So I should remake my atoms so that every time there is alpha it loses 2 electrons that the alpha takes with it?  (ok so 2 protons, 2 neutrons and 2 electrons-what is that called, is that now Helium?)

                               

                              Thank you.

                               

                               

                                • Re: questions on atoms
                                  Christine Brennan Schmidt

                                  This is a great discussion.

                                   

                                  One thing you have to remember is that electrons are not really attached to the atoms. They are attracted by their negative charge to the positive charge of the nucleus. So when the alpha particle leaves (and it has a +2 charge), it is less likely that the nucleas from which it originated has enough charge to hold an extra 2 electrons.  When I studied radio and nuclear chemistry, we didn't really worry about where the electrons went. They could go with the alpha particle, although it has lots of energy and may be moving 'fast' enough that the electrons don't find it before it leaves. But the electrons do leave somehow. They could attach themselves to a water molecule or some other electrophilic molecule.

                                   

                                  I do remember that although the nuclear configuration of a Helium and an alpha particle are the same, nuclear chemists (back in the day) used alpha to indicate that this particle originated from a nuclear reaction.  I'm not sure how important that is to your audience, but I suspect that is what a purist would say.

                                   

                                  As for beta emission -- the actually emission is essentially a high-energy electron originating from the nucleus.  It does leave the molecule.

                                   

                                  Electrons don't have to be associated with a specific atom, they can move around and can jump from atom to atom. That is the basis for many chemical (not nuclear) reactions.

                                   

                                  Michael Dowell - what do you think?

                            • Re: questions on atoms
                              Michael Dowell

                              I'm still agreeing with all you said, Christine, and about to back off one of my statements. The discussion is getting better and better because Beth wants to do this in comics/graphic novel form, and the story has to be clear enough that she can illustrate it.

                              If Beth can illustrate just the charges on the nucleus, just take away the alpha particle with its +2 charges and 4 mass units. It's true. The nucleus that's left is the " daughter" nucleus in your decay chain.

                              If you need to show what happens to the electrons when the alpha decay occurs, take 2 away from the cloud around the daughter atom and show the daughter as a neutral atom. Don't illustrate anything else that happens; it's complicated and I think, subject to correction, that you end up with a neutral daughter in most cases within about a microsecond. As Christine tactfully explained, the alpha particles may want those 2 electrons to become a neutral He but they are moving too fast-- when radium disintegrates, Rutherford was able to make a beam of alphas and bend it with electrically charged plates, so they get  several cm away from the daughter nucleus before they pick up electrons. If you had a neutral daughter atom that had not just received a lot of energy from the nuclear decay and you "offered" it an electron, it would give up energy to get the electron (the "electron affinity" of neutral Po is 1.9 eV and of Pb is 0.4 eV, so they would give you that for the first electron) and become an ion. But the nuclei have just been given about a million eV from the decay-- the rest goes away with the alphas-- and they are trying to give that away so they probably can't hold on to the electrons.  I doubt there's room in the comics universe to tell all that, so I'd just take away 2 electrons.

                              What about beta decay? As Christine says, the beta is an electron with more than a million eV; it's moving fast and gets away. You now have a daughter nucleus with one more positive charge and the original electron cloud, so you have a positive ion. If you don't show the electron cloud, only the nucleus, you are good. If you want to show the electron cloud anyway, I'd just show the beta electron going away and a +1 daughter ion.

                              Look, it has to be a compelling story and it can't tell anything untrue. But first it has to be pictorially compelling. If what I'm suggesting gets in the way of that, let's back off until we find the simple and true story that wants to be on Beth's page.       

                                • Re: questions on atoms
                                  Beth Bruce


                                  Thank you for your answers. So far what I am doing is pretty simple.  I also heard back from another person I contacted lately and this is the answer he gave me, his answers in red if it comes out.  Blue are my questions. He also recommended I consult a physicist with work:

                                   

                                  Question: Why are the electron shells with the exact number of electrons in each shell available for the radon and some other atoms, but not others?  Like you see Polonium 209 but not 218.  Which I believe that means Polonium 209 has 125 neutrons?  Is there something different about the particular atoms chosen to be on the chart?

                                   

                                  http://education.jlab.org/itselemental/ele086.html

                                   

                                   

                                   

                                  Radon 222           Electrons per Shell 2, 8, 18, 32, 18, 8

                                  86 protons

                                  136 neutrons

                                  86 electrons

                                   

                                  Alpha decay, emits 2 protons and 2 neutrons.  (Does it takes 2 electrons with it? which 2 electrons?  which orbit or shell? Does it matter?)

                                  Becomes Polonium 218. The resulting atom has two fewer electrons than it began with, as well as two fewer protons and two fewer neutrons, the alpha particle is the combination of those two protons and two neutrons.  The two electrons may remain with the alpha particle, but again they don’t matter a bit.  (really? Everyone keeps saying that electrons don’t matter).

                                   

                                  Question:  Does that mean an alpha particle has 2 protons, 2 neutrons, and zero, 1 or 2 electrons? Is this alpha particle an element of it’s own or just a particle?

                                   

                                  Generally atoms are found neutral, that is, the same number of electrons as there are protons in the nucleus.  So it’s easy to determine the number of electrons.

                                   

                                  Polonium 218

                                  84 protons

                                  134 neutrons

                                  84 electrons

                                   

                                  Alpha decay, emits 2 protons and 2 neutrons.  (Does it take 2 electrons with it, which 2 electrons?  which orbit or shell?)

                                  Becomes Lead 214.

                                   

                                  Lead 214

                                  82 protons

                                  132 neutrons

                                  82 electrons?

                                   

                                  Beta decay, a neutron becomes a proton and electron and the electron goes way

                                  Becomes Bismuth 214

                                   

                                  Bismuth 214

                                  83 protons

                                  131 neutrons

                                  82 electrons? 83

                                   

                                  Beta decay, a neutron becomes a proton and electron and the electron goes away

                                  Becomes Polonium 214

                                   

                                  Polonium 214

                                  84 protons?

                                  130 neutrons?

                                  82 electrons? 82

                                   

                                  Alpha decay, emits 2 protons and 2 neutrons.  (Takes 2 electrons with it?  Which 2?could be any 2, but expect it to be those on the outer shell as they are held most lightly.)

                                  Becomes Lead 210

                                   

                                  Lead 210

                                  82 protons

                                  128 neutrons

                                  80 electrons?  (I assume 82 now.)

                                   

                                  Beta decay, a neutron becomes a proton and electron and the electron goes away that’s right.

                                  Becomes Bismuth 210

                                   

                                  Bismuth 210

                                  83 protons

                                  127 neutrons

                                  80 electrons? Nope, 83

                                   

                                  Beta decay, a neutron becomes a proton and an electron and the electron goes away

                                  Becomes Polonium 210

                                   

                                  Polonium 210

                                  84 protons

                                  126 neutrons

                                  80 electrons? 84

                                   

                                  Alpha decay, emits 2 protons and 2 neutrons.  (Takes 2 electrons with it?  which 2?)

                                  Becomes Lead 206.

                                   

                                  Lead 206

                                  82 protons

                                  124 neutrons

                                  78 electrons? Nope, 82.

                                   

                                  And this is just my curiosity, it seems the more I know the more questions I have; Does the lead 206 float away, fall to the ground?  Would there actually be a visible source of lead 206 someplace?

                                   

                                  I don't have the means to make an actual cartoon, I will be making drawings to color and hope to put them in a coloring book soon that I will sell on my website and may hand out for marketing.  However you gave me an idea above to make an electron shooting out, and also I had thought to make an alpha particle.  So far my atoms are pretty simple, made with Powerpoint.  My character is Radon Rhonda, who is going to come out of a rock and float through the air, into a house, be breathed in and out, and she will escape through a radon mitigation pipe. So, not too technical at this point.  However I thought to make representations of the decay atoms as well, how she changes.  Realizing of course I have used color, but in real life I will point out she is invisible.Radon Rhonda

                                  http://www.radonbeyond.com/radon-rhonda.html

                                    • Re: questions on atoms
                                      Beth Bruce

                                      I think one of you above did answer a question about the alpha particle, and I will re-read your answers again when I have a moment so that I can study what you are saying more.  I think what I gather is that they go through changes, but I am looking for the neutral atoms, like a stopping place before they start changing again?  Also the alpha particle is an alpha particle in relation to the process of what is happening, but it is also the element helium? Is +1 daughter ion the element that remains?  Like the Polonium 214 (and actually should that be 84 electrons?)

                                        • Re: questions on atoms
                                          Michael Dowell

                                          Hi Beth,

                                          I do like Radon Rhonda. She's a cute way of getting the message across. Are you thinking of having her emit an alpha particle from time to time?

                                          About the electrons: when an alpha leaves the nucleus, it doesn't have any electrons, it's a +2 particle and because radioactive decay gave it a lot of energy, it is moving fast.  It would like to gain 2 electrons and become a neutral helium atom. It will pay 75,000 eV for the second electron and more for the first, and that is almost always enough to ionize any neutral ion that it hits. Remember that in the radon business, you detect ionizing radiation-- this is it. In beta decay, the nucleus kicked out an electron. That's also a charged particle and it can trip your detector, maybe by colliding with one of its electrodes.

                                          Remember also that when Radon Rhoda gave up her alpha particle, her daughter was Polonium and you said "+84 in the nucleus, are there still 86 electrons?" That would be Po-2. Well, Po is below O in the periodic table and we know that O likes 2 more electrons to fill its outer shell, so that could be. In fact, a neutral Po atom will give you 1.9 eV for the second electron and more for the first so it likes the -2 charge. Trouble is, now it has to go looking for a +2 ion or two +1 ions to combine with. Or, when the alpha particle left, it had enough kinetic energy that it could have knocked 2 electrons off Po-2 and left you with neutral Po. Every one of these outcomes is possible and happens some fraction of the time. You gain nothing by telling this messy part of the story.

                                          But you might want to say that after the alphas and betas have left the old nucleus, all the electrons that were around it eventually find homes in neutral atoms, either the new daughter atom or by forming He atoms with alpha particles. It's short and it's true.

                                          Finally, we have helium atoms and polonium atoms forming from Radon Rhoda in the gas phase. Does Po stay as a gas? How about the other decay daughters? Well, Rn is a noble gas and so is He; they don't combine with anything. But Po is a solid that melts at 254C and boils at 962C, and Bi is a metal and so is Pb so all of those want to do something else. How do they get out of the gas phase after they are born? Since we have simplified the story and present them as atoms, what would each kind of atom do? Po has the same electronic structure as O. If you had a free O atom, it would be pretty reactive with its neighbors. It could form peroxide with water vapor or react with the walls of the container. Bi might react with water or oxygen  or stick to the walls, and same with lead. A really short answer is "we make new atoms and they find chemistry to do", but that's another story.

                                          • Re: questions on atoms
                                            Donivan Porterfield

                                            Beth, I would second the observations of Christine and Michael that typically while discussing radioactive decay it is common practice to ignore the orbital electrons in the associated nuclear transformation.  While the orbital electrons around the nucleus are typically of preeminent interest to chemists (since they control chemical behavior and reactions) they are typically unimportant to most nuclear transformations.

                                             

                                            But to complicate matters in the relatively long period between nuclear transformations those same orbital electrons can influence the behavior of the atom.  So for example based on its orbital electron structure radon is a noble gas and thus can exhibit a considerable tendency to diffuse through air and soil.  Based on having a different orbital electron structure the polonium decay product of radon is not a noble gas and will be much more limited in its travels.  That limited ability to travel gives rise to its tendency - and that of other radon decay products - to “plate out”.

                                             

                                            The overall orbital electron structure of an element is dependent on the number of protons.  So Rn-222 and Rn-220 will have the same overall orbital electron structure given they both have 86 protons in the nucleus.  So given that similar orbital electron structure both Rn-222 and Rn-220 are noble gases and as noted above have the same tendency to diffuse through air and soil.  However, since Rn-220 has a much shorter half-life than Rn-222 it will effectively not get as far before it decays.  So that is why most discussions of the dangers of radon are focused on Rn-222.