Your periodic table is probably WRONG

I recently read an article which suggested that the periodic table that we love we see everywhere on the wall of your classroom on your t-shirt on your mouse mat perhaps even your boxer shorts may be wrong and that was a huge surprise for me so let me try and explain to you what the problem is here we've got the so-called ultra long periodic table where in these two bottom rows you have the elements listed in numerical order of their atomic number so they go here bare in 56 length and and 57 cerium 58 and so on and the one below you have radium 88 actinium 89 and so on this sort of shape doesn't fit very well on two walls in two books on two mouse mats on two boxer shorts normally you have one like this where this block of elements has been snipped out and put underneath and so lanthanum and actinium are under scandium and cerium lanthanum has a little red spot on top of it which means this lot had been left out and if you look at the numbers they jump from 57 to 72 and in the row below they're two stars for this row and you jump from element 89 to rather for diem 104 if we look at this rather unusual periodic table which was given to me by one of our YouTube fans what you can see is that there are two spaces here and instead of being 14 elements they're 15 elements underneath and lanthanum and actinium instead of being there have been put there now let me explain what the paper was that I looked at the paper which has a slightly and promising title measurement to the first ionization potential of Lorenz ium element 103 lorenz iam is this element at the end here is experimentally a triumph Lorenzi 'm is an so-called super-heavy element you have to synthesize it in accelerators it has a very short half-life the isotope they were measuring has a half-life of 27 seconds that means after 27 seconds half your lawrencium is gone and they were doing measurements on individual atoms and they were measuring a slightly obscure quantity the so-called first ionization energy which is the amount of energy required to remove the first electron and what they discovered was that Lorenzen has a very low first ionization energy and quite pleasingly you can see that the value that has been measured for point nine six electron volts is almost identical to what has been calculated by theory but what's this got to do with the periodic table what they're suggesting is that lutetium and Lorenz ium should be sitting under scandium an atrium that is the big break in the periodic table should actually come there rather than there so if you have the short form you would have the dot / radium you would go down to actinium you'd go along tan nobelium and then up here to lawrencium so what they're saying is that the properties of lawrencium are much more like each room and scandium than the properties of lanthanum and tinium are their argument is that the ionization energies of Lorentz 'i'm fit much better with those of this group then the ionization of lanthanum and actinium do so what they are saying bluntly is lanthanum and actinium probably shouldn't be in group 3 lutetium and lawrencium should be in group 3 because the way the periodic table is structured you would expect there to be elements at the bottom of group three now of course this is partly it Cerreta cool because there are only a few atoms of lawrencium have been made so it's not as if you are going to start using lawrencium for making catalysts or whatever but on the other hand it is quite important for understanding of the structure of the periodic table my memory of chemistry from school is rather hazy but I seem to recall we were told which elements went in which group depended on how many electrons were available for business in that outer valence shell so and we know how many electrons are in the outer shell surely for all of these elements so doesn't that dictate it now you're telling me it's done experimentally by ionization energies in this row here from scandium to zinc and all the others you're filling up the so-called DS shells of the electrons and down here you're filling at the so-called F shell what this argument boils down to is that they are saying that perhaps rather than putting in one D electron and then filling up the F shell you put in fill up the F shell and then add the D electron it could be that the break is different in the two rows it could be that lanthanum is here and Laurentian is there and that the break doesn't happen in the same place in the two rows that would be real mess for the people who draw periodic tables but what we're interested in is what nature is like not how easy it is to draw it so we're braving the elements ready to repeat the experiment that we did quite some time ago heat that tool is warm and put it in the chlorine the chlorine will oxidize it to iron chloride

Channel: Periodic Videos

Views: 663,838

Keywords: chemistry, periodicvideos, periodic table, periodic table of videos, professor, martyn poliakoff, nottingham, chemicals, elements, lawrencium, actinides, lanthanides

Id: J1zNbWJC5aw

Length: 6min 34sec (394 seconds)

Published: Wed Aug 12 2015

Reddit Comments

[u/kempff]

"Wrong"? Looks more like one of those "off-by-one" errors that plague computer programmers.

The designations of the "Group" columns have undergone enough revision just in my lifetime that I no longer hold my students responsible for knowing the column-labels for tests and homework and I let them name the columns after the topmost element. (The halogens, for example, are "the fluorine column", etc., and it seems to help, as they seem to be thinking good thoughts like "Well barium acts like calcium and chlorine acts like fluorine, so the reaction products should be BaCl2, like CaCl2".)

But the exact position of the lanthanides/actinides has always been confusing for me in the condensed grid. Are the "f-fillers" all in the scandium column? No, they are a set of columns all on their own, just like the p-fillers. Do the serieses begin with La/Ac or do they begin with Ce/Th? Well La/Ac are definitely in the scandium column since they are both d1s2 like scandium, so the serieses must begin with Ce/Th, because those are both supposed to have a single f-electr---wait, what??? Another exception to the rule? And Lr/Lu are also d1s2? Oh Mendeleev, you haunt me.

[u/DamagedHells]

I finished my graduate classes a little over a year ago, and we had a class dedicated to what was essentially the periodic trends. This replacement on periodic tables was a question on the exam.

[u/gavilin]

This is actually how I always thought the periodic table WAS set-up, as it makes the most intuitive sense when you think of the f-block as coming before the d-block in basic principles. It actually took me until my junior year of high school to realize that it's normally presented the other (normal, maybe wrong) way round.

[u/smithsp86]

I've always felt it wrong at that point because of the orbital filling argument. Lanthanum should be filling its 4f orbital so it should go on the f block of the table. But I'm also one of those heretics that thinks helium should be above beryllium because both have a full s orbital.

[u/Quetzalcaotl]

Compared to what it is now, wouldn't this "new" way of organizing the f-block be more correct anyway? It never really made sense to me that electrons would skip levels in the manner they teach in primary school.

[u/Hayarotle]

This always bugged me, how the lactinides and lantanides were apparently towering over scandium, which made no sense considering the pattern of the periodic table indicating orbitals. Nice to see it is actually noted.

[u/-TheWiseSalmon-]

Turns out my Periodic Table bookmarker was right; Lu and Lr are in d-block like the new evidence suggests they should be.

[u/tofu_popsicle]

Nooooooooo! My favourite mug at work is a lie!!

** watches video **

Oh. So is this saying that Lawrencium and/or Lutetium are actually d-block, not f-block? OK, that makes sense looking at the details now... but I'm not going to chuck out my mug after all.