As a person who is learning english, it's very relaxing listening to the professor. He doesn't speak as fast as most people do, and his words are very well pronounced, in a way that it is easy for even me to understand every single word he is saying. Also he knows very well how to explain himself. Keep up the great work professor. Love your videos and your hair.

@Soaring-Dragon

4 жыл бұрын

Well I hope you learn chemistry as well by seeing these videos and hopefully Michael gets well soon

@crystallopez1397

4 жыл бұрын

Your right I’m 7

@KuK137

4 жыл бұрын

@Evi1M4chine Too soon :(

@michaelmcinerney2853

4 жыл бұрын

He speaks, what would be called, the Queen's English.

@levitheentity4000

3 жыл бұрын

I'm the same country as you (Brazil), I speak english for a while, and even to me his English sounds very relaxing...

This man looks like science

@reeee4336

5 жыл бұрын

@AstronomyToday **laughs in chemistry**

@TrueMose

4 жыл бұрын

*_h e l p m e t h i s i s n t a j o k e_*

@sebastianstewart6894

4 жыл бұрын

Well I guess you have been successfully brainwashed.

@venyeet5021

4 жыл бұрын

He is Science.

@protocol__3542

4 жыл бұрын

Sammy help meth is isn’t a joke

that awkward moment when you're actually wearing your periodic table tshirt while watching this video AND Lutetium and Lawrencium happen to be in group three on that shirt

@NoahTopper

8 жыл бұрын

Chris Orita Had to check my shirt in my closet. Mine's the same. Weird...

@tohopes

8 жыл бұрын

Chris Orita Better go order a tall latte to go with your hip shirt.

@jovetj

4 жыл бұрын

But what did your boxers have on them?

@scrambledstatesofamerica837

4 жыл бұрын

Actually, Lanthanides and Actinides aren't part of ANY GROUP AT ALL!!

@paulkennedy8701

4 жыл бұрын

@@scrambledstatesofamerica837 No. But lanthanum and actinium are. (According to the conventional conception.) The lanthanides and actinides don't include La and Ac but merely take their names from them. If this video is correct it isn't La and Ac at the bottom of that group; it's lutetium and lawrencium, in which case they are not members of the lanthanides and actinides. (And possibly La to Yb and Ac to No should be called "barides" and "radides".)

"What we're interested in is what nature is like, not how easy it is to draw it." This simple sentence beautifully articulates what science means to me :) -Nathan

@tomaszlosinski875

4 жыл бұрын

Why did you sign your name at the end?

@beefchicken

4 жыл бұрын

Tomasz Losinski why _didn’t_ you? -beef... chicken

@3snoW_

4 жыл бұрын

You quoting yourself makes everything awkward to quote! « "What we're interested in is what nature is like, not how easy it is to draw it." This simple sentence beautifully articulates what science means to me :) -Nathan » -Nathan

"Simulation of Brady's high school chemistry memories" haha

@douglasstrother6584

4 жыл бұрын

They could read my mind also!

Am I the only one that is happy after watching this video?

@marlonyo

8 жыл бұрын

Brendan Nicholson why would you think that

@bobfl42

8 жыл бұрын

Brendan Nicholson For me I am neither happy nor sad but I am very confused now.

@BrondanStifflson

8 жыл бұрын

marlonyo I don't know. Some people don't like change haha

@BrondanStifflson

8 жыл бұрын

+Robert Fletcher it just has to do with the theory that lawrencium shares more properties in group 3 than actinium does.

@gildedbear5355

8 жыл бұрын

+Midnight Creature we also have words for people who lump huge groups of people into single categories and then judge them. As a religious person who embraces changes in scientific understanding your statement offends me.

Thanks for this video.

@bloggervista

8 жыл бұрын

Eugene Khutoryansky and thanks for your physics and calculus videos

@SomeOne-lx6ms

4 жыл бұрын

I loved your higher dimension shapes videos

That quote at the end should be emphasized more: "What we're interested in is what nature is like, not how easy it is to draw it." Pretty much should explain science to sceptics.

@wiiztec

2 ай бұрын

The fact that the abridged version is used everywhere because it fits better should tell you that is not really the case

Now we know what boxer shorts the professor wears

You talk a lot about Lawrencium here, but wouldn't this be much easier to test with Lutetium, which has a stable isotope and is thus significantly easier to observe and play with? And if so, why didn't we know this already?

@zh84

8 жыл бұрын

Quite.

I think that Scandium and Yttrium should be placed above Lutetium and Lawrencium rather than the other way around. They all share the same property - one electron in a d-orbital.

This is fascinating. Thank you, Professor Poliakoff, for explaining it in a way I can understand.

@themanwiththepan

8 жыл бұрын

Raina Ramsay professor? He's a sir!

@RainaRamsay

8 жыл бұрын

And also a professor.

@LeftFlamingo

8 жыл бұрын

themanwiththepan I agree. Sir Martin, the professor =)

@rich1051414

8 жыл бұрын

What order of titles is correct anyway? Professor of Chemistry Sir Martin Poliakoff? Sir doesn't sound correct to me unless directly proceeding the full name.

@LeftFlamingo

8 жыл бұрын

Only the given name is used in verbal communication and description in conversation (which this would arguably be), except when distinction is necessary. Then the surname is added. In this case, since it's clear to all who is intended, "sir Martin" would be correct. According to purists, "professor" should not be used in conjunction with "sir". It would also be redundant in this case. In a description (in writing) where very specific distinction is necessary I would suggest "Sir Martin Poliakoff, Professor of Chemistry" When addressing sir Martin in a professional context, I would say it is completely acceptable to address him as professor. In all other instances, "sir Martin" should be preferred. Of course, his own wishes on how to be addressed should also be respected.

I'm learning more in these few videos than I did in an entire year in high school chemistry. That's a testament to how well-presented these videos are, and to how bad my high school chemistry teacher was, who had absolutely no interest in teaching it.

I noticed this problem back in chemistry when we learned about the sub levels. You talked about this at the end of the video and I always thought that's the way it should be done. It makes sense that the left is s sub level and the right is p then the middle bit is d, but I always thought it would make sense for the f to be put before all of the d, therefore making La and Ac part of the bottom and Lu and Lr should be up with the rest of the d sub level.

I always suspected that Scandium and Yttrium would go over Lutetium and Lawrencium owing to the relative stability in ordinary air found at the Lutetium/Lawrencium end of those elements in comparison to the Lanthanum/Actinium end which tend to oxidize quickly from pure metal into powder. Scandium and Yttrium are stable in air like Gadolinium through Lutetium. So now there is only all the more (and much stronger) reason to rearrange the periodic table in that manner.

Is there a "corrected version" which I print out and hang on my wall? :D

@ionlymadethistoleavecoment1723

8 жыл бұрын

Well it is a proposal so we'll see if the table changes

@MathHacker42

8 жыл бұрын

pcfreak1992 I wouldn't say that the traditional version is incorrect, but the version described in the video is certainly better.

@roidroid

8 жыл бұрын

pcfreak1992 just take your scissors and HAVE AT THEE!

@pcfreak1992

8 жыл бұрын

Jan Troker sogar auf Deutsch, danke! ;-) #Like

@rich1051414

8 жыл бұрын

MathHacker42 Well if one is certainly better, then that one is also certainly more technically correct :P Science should not be held to the same limitation of those of 'common knowledge', and they should fix it sooner rather than later. No point in keeping something that turns out to more 'less right' simply because of familiarity. Besides on those lower two rows, no know cares about anyway, so having them in an order which describes behavior more accurately should be of highest priority, as this was the point in the table to begin with.

And that folks is why Science is awesome. We find out what's wrong, and WE FIX IT!

@RedHairdo

8 жыл бұрын

***** Sometimes. Or rather, that's the tendency, anyway. "Sometimes", because who knows how much else science is wrong at? And who knows if we will ever catch each of those mistakes? But then again, I don't know of any other better way.

@FelixAB88

8 жыл бұрын

+youtubasoarus ... until somebody else proves us being wrong. ;-)

@2adamast

8 жыл бұрын

That's why science often stinks, replacing a real element with the memory of a shadow because of some paper

@kenanhusayn3765

8 жыл бұрын

+youtubasoarus, yeah we do ;)

@lawrencedoliveiro9104

6 жыл бұрын

“The great tragedy of science, the slaying of a beautiful theory by an ugly fact.” -- Thomas Henry Huxley

I laughed pretty damn hard at the simulated chemistry memories. My memories are about the same. ;p It's amazing how Martyn and the rest of the gang make what would normally be such mundane and boring subjects into interesting and understandable information. If only I had chemistry teachers like these in high school.

@slendy9600

8 жыл бұрын

ye i know what you mean i had a pretty fun chemistry teacher, it was great... not as fun as prof. poliakoff though with his period table boxers XD

@SleuthSayers

8 жыл бұрын

slendy9600 My HS chem teacher was the ag teacher… seriously, agriculture. His chemistry skills were so great, he could almost make tea.

@liamsmith331

5 жыл бұрын

I mean he doesn't have to make us do actual work or calculations so there's that

Great video as always, Brady. Have you considered doing a video on the chemistry of spider silk and what makes it so strong? I'd love to see such a video.

This guy makes chemistry fun lol.

@jpian0923

7 жыл бұрын

Thanks to the classroom of KZread, that world you imagine, can exist, and will.

@TaekTara

6 жыл бұрын

I would love this guy as my chemistry professor 🤓

Thanks so much for these videos. Great explanations and they make me endlessly curious. Don't stop making them!

Lawrence elementry, the school I went to, was named after the guy that discovered lawrencium.

@sorinnorris

8 жыл бұрын

***** cool story bro

@ffggddss

4 жыл бұрын

Not sure of the discoverer, but the element (#103) was named after Ernest O. Lawrence. * So was Lawrence-Livermore Lab. * E.g., Albert Einstein didn't discover einsteinium (#99), Enrico Fermi didn't discover fermium (#100), etc. Fred

@ffggddss

4 жыл бұрын

@glyn hodges Yeah, so was that elementary school - where'd that go? Fred

I was arguing this during my A Levels in 1977 it seemed logical that Sc and Y belonged over Lu and Lr, rather than over La and Ac. Which means that Lu is not a Lanthanide and Lr is not an Actinide.

but isn't this obvious? it should fill the f-block first after the s-block, which means that lanthanum and actinium should be the first elements of the f-block. Also, when you write the whole table out without the f-block elements drawn off to the side, lawencium and lutetium fall in line with scandium and yttrium.

Anyone with enough of a background in chemistry to understand the ground-state-energy based order of filling of atomic orbitals based on quantum numbers, consistent with Hund's rule (AKA undergraduate General Chemistry I) could realize that Lutetium and Lawrencium would be more appropriate to include in Group 3 below Scandium and Yttrium instead of Lanthanum and Actinium, without needing any experimental validation based on first ionization energies. I'm not sure why Lathanum and Actinium ended up included there by default, considering that you'd think it was chemists that constructed the commonly-used periodic tables; but considering that only chemists of sufficient ability to recognize the mistake would likely be doing work in which it would matter, I suppose it's of minimal consequence. Still, for the sake of scientific accuracy, this is an error that should probably be corrected in textbook periodic tables; thank you for spreading awareness of it.

I remember learning that the f-block is extremely irregular in terms of which electron shells are filled before others, so whichever way you draw it, there'd be exceptions in the elements the middle of the block (that is, some of those f-block elements have the first d electron, and some don't).

Cool I have been doing that since around 2004 or so when looking at the table and looking at the electron configurations. Plus it makes it easier when showing new students the diagonal rule!

Totally love it! That so much is now known about the structure of the atomic world, conversations about the table that contains them can be conducted with such detail is amazing. I must wonder what Mendeleev would make of such discussions.

I love these guy, he look like science in human forum

@suwinkhamchaiwong8382

5 жыл бұрын

Almozayaf Roman form*

This is exactly what I've been thinking for a long time! Thank you!

Brady, thanks so much for asking about the orbitals! That was burning in my brain the entire video.

This always bothered me in chemistry class. It was like "F orbitals filling" (or "D orbitals filling") but the layout was all wrong.

@gordontaylor2815

8 жыл бұрын

+tohopes It was the best they could do with the knowledge they had at the time, can't blame the table makers for that. (You make a lot of assumptions when it comes to the properties of these high number elements, only because it's really hard to test anything!)

@tohopes

8 жыл бұрын

Gordon Taylor Yeah but given that the layout seemed wrong to me years ago when I was a simple school student, I have to wonder to what extent or for how long it's been just simple inertia that has kept the table this way.

@jonatankelu

4 жыл бұрын

I had the same experience.

Once again informative info. I find this stuff fascinating, though I haven't studied chemistry since 1978 in high school. I'd love to see a video that goes through the periodic table and see a physical example of each.

This model with Lawrencium in the same group as Yittrium makes more sense to me and I'd think would actually make it easier to draw and would be intuitive as it means that the first group of transitional metals isn't separated from the others by the lanthinides and actinides.

I have no understanding of 90% of what your talking about but I am fascinated by all of this and with each video I learn a little something.

And science provides evidence for something I have believed since I was fourteen. It feels good to be right.

@Fenriswaffle

8 жыл бұрын

Mara K Science affirming a belief theory or hunch can sometimes be boring, it gets interesting when an inconsistency can grow to through your entire ruleset out the window.

@MaraK_dialmformara

8 жыл бұрын

***** It's interesting because science teachers have been telling me I'm wrong all my life, and now, if I ever cared to meet my high school chemistry teacher again, I have some official support for my understanding of the world.

@MaraK_dialmformara

8 жыл бұрын

You underestimate how boring and pointless my high school chemistry class was.

I remember finding out about something like this before. This isn't the only place where the electrons fit into the orbitals in a weird way, either, but it might be the most confusing one.

Wondered about this for a long time. Thanks for giving plausibility to my suspicions.

Haven't seen a video from this channel in a while...Glad to see the professor again

Please can you try raise the recording volume. Its very hard to hear on max volume on ipad

My goodness, how I wish Sir Poliakoff was my high school/college chemistry teacher!!

It depending on the energy condition like The E= k + g+h+ mass. Thank you professor you clear up something I am uncertain about.

Phew somehow the periodic table I use is correct. However the one on my coffee mug is the traditional incorrect one.

This professor is really cool in how he explains things!

it looks better even just by numbers. the transition part goes together, in series. You can of course make a super-long one with 14 extra places then wouldn't cut off scandium and yttrium to place on the left, they stay with the transition metals. I tend to see the asterix is instead of having a very long table, due to being the values of the next electron energy states rising, then on those rows the electrons fill in those shells THERE, before having enough to make the transition metals in the last two rows.

I wonder about Luteium. While it is not exactly common, there are certainly visible amounts of the element present for ionization potential measurements.

Wow i didn't expect that this should be a theme to disccuss maybe you are right Sir Prof. Poliakoff, because the element periodic table, is about the properties of the materials, and if de Lu and Lr fit better that way, shouldn't be place instead where are the La and the Ac.

Fantastic video. You explained it so well.

Thank you for this video. I've wondered for a while whether the periodic table was indeed wrong or not. I knew that the order in which the orbitals were filled (accending atomic number not the order for K, L, M, O, P, Q shells) was s, f, d, p and that therefore La and Ac were the first elements of f. It seems logical that the orbitals were filled completely before going to the next and that a single 'd-atom' before the f-block was wrong. But I'm no chemist and I don't know if the properties of the groups matched.

Page 13-14 actino- or before a vowel actin- combining form. 1 indicating a radial structure: actinomorphic. 2 indicating radioactivity or radiation: actinometer. [from Gk, from aktis ray]

I noticed this problem a while ago, and it bothered me throughout AP chem. I don't think there really needs to be a whole paper to argue that the d-block should all be together and that the f-block should all be together, to me that's just common sense. I wouldn't say the traditional version is wrong just for grouping elements in a way that doesn't match their properties, I would just say it's poorly designed.

Wow, fascinating stuff. Even if this does cause a bit of a mess, the fact that such a big assumption in the structure of the table might be changed because of experiments with super-heavy atoms is still incredible. To those who say what's the point of experimenting with such "practically useless" elements, well this is the reason

I always like to put Lanthanium to Lutetium below. It fits to nicely with groups 4 to 18, even though they probably have nothing to do with each other.

also reactivity decreases going down the D block and increases going down the S block but lanthanum is more reactive than yttrium which is less reactive than scandium (lutetium is less reactive than yttrium so it fits better as eka-yttrium than lanthanum does)

Wow. This is just fantastic. For videos like this one is that I love watching this channel.

Look for "Górski's Atomic Core Based Periodic System" ("rdzeniowy układ okresowy pierwiastków" in polish) which we are learning at Warsaw University of Technology. It makes some "unique" properties of elements (like the one mentioned in this video) quite obvious.

the funny thought in my head is that even though I am just about to start year 10 in high school, I have always thought that lutetium and lawrencium belonged under scandium and yttrium, rather than actinium and lanthanum, and when drawing the extended periodic table (as one table, rather than two) I've always drawn it as such. Thank you for showing me a reason not to feel crazy by thinking this seemed more true than many people would think. Now I can show my friends this video to explain to them why I do this haha XD

The movement of the elements after lanthanum and actinium is why we call that block underneath the 'lanthanides' and 'actinides'. So if the cut off point is now after barium and radium, should they not be the 'barides' and 'radides'?

Can you please make a video on alternate periodic tables? I'm thinking about the arrangement that professor Gil Chaverri (from the Unversity of Costa Rica) made in the 60's. I'm sure there must be an updated version somewhere. Thanks.

Small correction to what Sir Martyn said: It is not the d/f shells that are being examined (because those do not exist), but rather the d/f subshells which are the orbitals belonging to the principal quantum number (1, 2, 3, ...) for each shell (M, N, L, ...). It's basically semantics put it might lead to confusion.

Hey brady! A suggestion and wish from me would be a longer and more in depth video about the "Island of stability".

In comparison to Lawrencium, surely a similar analysis of Lanthanum vs Lutetium would be a lot easier, as substantial samples could be procured.

fascinating. Nice job.

I always wondered why the d-shells of lanthan and lutetium would receive one electron before the f-shells are filled, now I have an answer that indeed the f-shells come first. Thank you, Professor!

Thank you for sharing this.

With my school book La and Ac are in the lower row, but Lu is also in the lower row (at the end of it)

My old periodic table has placeholders under Scandium and Yttrium. And Lanthanum and Actinium are at the start of the extra rows. But it goes only up to 109.

Well, it also depends on the molar mass of the atom, numbers of electrons, protons and neutrons. There might me some irregularities regarding the properties of the atoms. But that was interesting still. Thanks for sharing.

In the end he says that the thing we care about is what nature is like and not how easy it is to draw it, but in the beginning he says that We have this alternate way of drawing the periodic table because else it is difficult to draw! It seems like we sometimes choose to care about the aesthetics of the periodic table and sometimes we don't, to prove a point about a drawing... Either we care about how it looks or we don't.

Another well-done video, Brady. Good work!

Sir Martyn, what is your personal feeling on the matter? Do you think there needs to be more research on ths matter or do we need to begin considering changing thee table?

Research electrical nuceosynthesis via "Z-pinch" effect, then tell us how many additional heavy elements are possible (or rather, likely).

I finding myself amazed by a table. Good work!

***** The shell bit was rather interessting please do at least one video about that^^

You discuss the case of Lawrencium that is not easy to observe but what about Lutherium, does it present a similar behaviour since it should be more easily available?

Although they do well to show it's physical properties and the ability of Lawrencium (Lr) to have an electron taken, wouldn't further testing on other Lanthanides and Actinides be required to determine if a Table shift would be necessary? My reasoning, is that Flourine has some pretty remarkable properties given it's density and it's strength to hold onto electrons. Some measurements of the energy to remove an electron from a sample is incredibly difficult even for it's location (disporportional) I guess what I'm saying is what if this is a hiccup in the Table? As in the physical properties of the element don't match what we would expect because there's something fundamentally different about valence electrons in this part of the table? Now, I'm not an expert. Just hoping to elaborate further, with some moderate skepticism. (Don't eat me up internet, please)

This eas really an interesting video. I'm a little confused but I think I got it. I know working with heavy synthetic elements like those sre incredibly hard, I remember I think ot was in the seaborgium video there was a questjon of why even study these super heavy atoms if they are so hard. I guess this is why, to test the models and the theory.

Here's a question that's been on my mind for years and i've been following a lot of the science dedicated channels and no one is addressing it. Why do atoms give up their neutral charge in favor of having their "outer shell" filled? it's not gravity or electromagnetism or the strong or weak forces, so why does CHEMISTRY happen? please refer me to a video or make one. thanks

@Bladeninja76

8 жыл бұрын

Hi, since you're asking about atoms I should mention that it's usually only metals and noble gases that are monoatomic (on their own). Anyway, atoms don't really need to have neutral charge. When a reaction involves transferring electrons, it's mainly about which atom is more electronegative. It's simple electrostatic attraction between one atom's nucleus and another atom's electron. As for the outer shell, advanced courses in chemistry will talk about stability based on subshells being half full or full.

@jacobvanoosterhout5281

4 жыл бұрын

Electrons from high energy orbitals will tend to settle down in lower energy orbitals. Take sodium chloride. Sodium has a relatively low first ionization energy of ~500 kJ/mol (so little energy is required to remove an electron, or it's a high energy electron.) Chlorine has a much higher 1st IE of ~1200 (much more energy required to remove an electron, so the electrons are lower energy overall). The overall energy of all electrons is smaller if sodium has zero electrons in its 3s orbital. Chlorine has space in its much lower energy 2p orbital to accept an electron. With molecular reactions, a similar argument applies, but the orbitals are much more complicated. Molecular Orbital Theory states that electrons are spread out throughout the entire molecule in orbitals, much like atomic orbitals, only with WAY more math involved. A reaction occurs when one molecule has a high energy molecular orbital that is occupied by electrons, and another molecule has a lower energy unoccupied molecular orbital. The higher energy electrons settle down into a lower energy orbital, reducing the overall energy of all electrons involved.

@n.l.4025

4 жыл бұрын

Jacob Van Oosterhout (continued) releasing the Potential Energy stored by the high energy electrons.

Professor, a quick question that I am wondering about. Wouldn't it be easier to check on the properties (and maybe ionization potentials) of Lutetium and Lanthanum and see with match the group 3 family? It might have been mentioned in the paper. Just a thought

Great video Sir.

I've been thinking this for a long time. Some periodic tables have Sc and T as actinides and it didn't make sense. I also thought all transition were d like Lawrencium and Scitrium.

that does seem somewhat more intuitive based on the the idea of shells that it wouldn't start the F-Shell before the D-Shell. What was it that lead to the current structure of the table? I assume there was some experimental data to suggest it was structured as it is?

Brilliant! As usual Martyn.

How do u determine electric potential of radioactive material? How do you determine valancy when oxygen has 1-4 elements bonded to it depending on compound making it both shelled and orbital?

Earth's mantle and meteorites have essentially constant values of Y/Ho. This means that the preference for these elements to enter the crystal lattices of the different minerals and liquids that make up bulk planetary bodies is essentially identical. So from a geological perspective it should be Ho directly below Y, not La or Lu

I've always thought that irrespective of how the electrons pile up, the periodic table should list the elements with the presumption that whole subshells (or whatever they are called) should be presumed to be filled before going on to the next one. Yes, perhaps the rare earths and actinides (i.e., the cutout rows on the canonical periodic table that was around until the community got around to naming the elements 104 & up) have the f shells fill out after a single d shell electron gets filled - but if that's the attitude, then what about Au, in which there is only 1 s shell electron in the outer shell? According to the periodic table, it should be set aside somewhere else because of its unique configuration. The answer to this is that the table should go on the presumption of the shells filling up subshell by subshell.

I like the last statement.... "What we're interested in is what nature is like, not how easy it is to draw it!"..... Brilliant.

i love chemistry, it has always been my strongest discipline ever in school, but this man i understand he knows a lot more about chemistry than i do, but he looks like a mad scientist like those ones who would blow up a lab in a crazy experiment (do not take it personally, i am only joking) respect 🙏🙏🙏

I have been wondering about that ever since I saw the "shortened" periodic table... I thought maybe they have their own reasons but I didn't expect that they were wrong...

You know what? Adopted & accepted because clearly explained concerning the given ionization entrophy of the questioned elements. Periodic tables require updates now to be consistent with element characterization within that table. And wether the break is different and not consistent within the upper and lower rares group, this has to be re-researched for to determine where the groups actually have to be separated for proper characterization. Maybe there is ony a minimal discrepancy. but even fractions can make a diffference.

Excellent video.

If I were drawing up the periodic table, I'd put the three leftmost columns (lithium to Francium; beryllium to radium; scandium to either actinium or lawrencium) to the right of the noble gas column! That's because they balance out the rightmost columns in valence.

Mind Blown. Loved the video.

Isn't this something physicists kinda knew already? I've never seen a physics textbook suggest that d and f orbitals would always be so close in energy that you will always end up with one (!***) electron in the d orbital, then fill up the preceding f, and then the rest of d. The energies for orbitals are in pretty distinct levels in any diagram I can think of (which may or may not be a simplification). I always thought of the old way of writing the PSE as historical artifact and maybe also related to some chemical properties not adequately explained by electron configuration alone. There must have been *some* reason not to go for the much simpler explanation of d and f filling neatly after each other, right? *And why exactly one and not two? Aren't unpaired electrons usually higher in energy than paired ones (unless they can't pair because their is spin pointing the same way, or they are in some weird hybrid configuration)?

I'm encouraged that we are interested in what nature is doing. Could somebody please convey this ideal to the cosmologist?

In his video on Iridium. He is sporting a periodic necktie

Thank you for covering my doubt from 3rd grade. I always usè to wonder why they are put separately.. thank you

These elements made in accelerators don't seem to be stable for very long. What possible use could they be? Would there be an isotope that is stable? Has there ever been a stable element made in an accelerator? Are the conditions not right when these elements are made.

Wonderful explanation. Thanks so much. I always look at the table as Nature's recipe book. It's not what you have in your cupboard, it's how you put what's in your cupboard together. Leptons, baryons, fermions, quarks, gluons, neutrinos, all of the particles and force-fields : assembled and re-assembled in different configurations. Like having 33 million recipes for chicken soup, I mean Reality. :-)

One question that I can't see anyone addressing: before this experiment was done, what was the reason for people putting lanthanum (La) and actinium (Ac) in Group 3? Was there a reason to do with theory? To do with earlier experiments? Or was it just an arbitrary choice?