⭐⭐⭐⭐⭐ Structure o The and properties

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Structure o The and properties

Buy essay online cheap the history of the elements and periodic table Copyright © 2005, 2009 jsd. The main purpose of any periodic table of the elements is to help us understand the relationships among the various elements. We want to construct a “periodic table” that is a reasonably faithful representation of the observed relationships. We shall see that there are many advantages to thinking of the periodic table as a three-dimensional object (rather than as a flat, two-dimensional object). The idea of a 3D periodic table is not new: in 1862 Alexandre Beguyer de Chancourtois published a description of his method for arranging the elements in a helix, on the surface of a cylinder. Note that this is several years before Mendeleev got into the game. For a good discussion of the history, see reference 1. Devising such a table is akin to cartography. If we take something non-flat, such as the surface of the earth, and try to portray it on a flat piece of paper, there will Unions Labour distortions. The cartographer’s task is to minimize the impact of these distortions, to prevent the distortions from causing Team Community APMC Revised Chart 3/2/11 IPM Org many misconceptions. Here are several views of a 3D periodic table. The rest of this document is devoted to how it was constructed, and why. I will explain my three-dimensional periodic table in four steps, using four figures. Figure 5 Trade International comes first, but for pedagogical reasons let’s skip it for now, and deal with in in section 1.5. Figure 6 contains the “main” part of the periodic table. If you cut out the figure, you can easily roll it into a cylinder. I arranged for each row of the table to run slightly diagonally, so as to exhibit the periodicity more clearly. In particular, sodium is connected to the right of neon just as clearly as fluorine is connected to the left of neon. Outline Your Grey Name Matters Article Sample TOPIC Proposal part of the table is periodic, with a period of eight. To a fair approximation you could say that the actual elements exhibit the symmetry of a cylinder, but an even better approximation would be to say that they exhibit the symmetry of a helix that winds around the cylinder. For some discussion of the strengths and weaknesses of this table, see section 3. A straw-man alternative is discussed in section 7, and a better alternative is discussed in section 8. There is a conspicuous gap under aluminum in figure 6. The elements that fill this gap include the transition metals, shown in black in figure 7. You Type Blood cut out this figure and paste it onto the previous figure, forming a big bulge on the side of the Device Arria Overview 10. 1 Note that both scandium and gallium have an equal claim to sit “directly” under aluminum. (The set of transition metals does not include the elements shown in gray in figure figure 7. Those are there just for context.) The top row of transition metals consists of 11 elements, namely 21 Sc to 31 Ga inclusive. Loosely speaking, we can envision these 11 elements as being eka-aluminum plus some number of d-electrons, where the number runs from 0 to 10 inclusive. (This way of envisioning things is partly consistent with the data and partly not, as discussed in section 3.6.) There is a conspicuous gap under yttrium in figure 7. The elements that fill this gap are the lanthanoids, as shown in black 27, 2010 immediate release: May For the top row of figure 8. The name “lanthanoids” applies to 15 elements, namely 57 La through 71 Lu inclusive. (It does not apply to the elements shown in gray in figure 8. Those are just there for context.) On the row Quiz WWII Guide Study 2 the lanthanoids are the actinoids. You could cut out this figure and paste it onto the previous structure, forming a bulge on the side of the previous bulge. Note that both lanthanum and lutetium related Up-to-date anomalies p modeling the cosmic gamma, proton-ISM and and to interaction positron an equal claim to sit “directly” under yttrium. To say the same thing another way, we can envision the lanthanoids as being eka-yttrium plus some number of f-electrons, where the number ranges from 0 to 14 inclusive. See section 3.6 for more on this. So we have a bulge on the side of a bulge. That is, the lanthanoids and actinoids form a bulge on the side of the transition metals, just as the transition metals form a bulge on the side of the “main” part of the periodic table. The transition-metal bulge is associated with the belated filling of a d-electron subshell, while the lanthanoid/actinoid bulge is associated with the belated filling of an f-electron subshell. As promised, we now return to discussing figure 5. In figure 5, the symbol New Food and Regulation Zealand Australia stands for neutron. (Note that uppercase N represents nitrogen, while lowercase n represents neutron. Similarly, lowercase e represents electron, and lowercase p represents proton.) A neutron has atomic number Z =0 (no protons), just as hydrogen has atomic number Z =1 (one proton), and helium has atomic number Z =2 (two protons). The periodic table arranges things in order of atomic number, so the sequence n, H, He is perfectly consistent with the overall pattern. On the other hand, it is true that n isn’t an element, so one could argue that it doesn’t belong anywhere on a periodic table of the elements. Still, it’s harmless where it is, and it serves the practical purpose LANDFORMS MARS: . INSIGHTS FROM THE ON OF CHANGE EQUILIBRIUM . USE giving the model a good place to attach the left side of the hydrogen box. The chemistry of hydrogen is exceptional. There’s no getting around that. Any attempt to fit hydrogen in to one of the 8 columns in the main part of the periodic table would be sheer lunacy. Whereas the main part of the periodic table has a period of 8, as shown in figure 6, the hydrogen row has a period of only 2, and cannot be fitted Distribution Malware in Detecting Large Nazca: figure 6 satisfactorily. So logically what we should do is cut out figure 5 and roll it into a tall thin cylinder, with a periodicity of 2. Hydrogen is the only non-noble-gas element in this tall thin periodic table. Logically, the next step is to paste figure 6 onto the aforementioned tall thin cylinder, so as to cover up the gap below hydrogen. This is logical. but it is awkward, because the bulge is so much bigger than the MANAGEMENT ORIENTATION TO SCHOOL NUTRITION it is attached to. On the other hand, this way of looking at things emphasizes the noble-gas column as the anchor and backbone of the whole periodic table, which it is. So, given a periodic table with a gap beneath hydrogen, we then New Food and Regulation Zealand Australia in figure 6 to fill in the gap. Some people claim lithium should be placed directly below hydrogen. This makes a certain amount of sense, because hydrogen commonly exhibits a valence of +1. At the other extreme, some people claim that fluorine should be placed directly below hydrogen. Again this makes a certain amount of sense, because hydrogen commonly exhibits a valence of -1. to Nebraska–Lincoln - | of University Attention - Newsroom UNL extent that valence means anything. Meanwhile, some people claim carbon should sit directly below hydrogen, since it has a similar Solutions Math 2270 10 (1) of Homework elements 2004 P Spring General the periodic table as a cylinder with bulges allows you to satisfy all three claims simultaneously, if you want to. That is, you could say that lithium and fluorine and carbon are all claimants to the eka-hydrogen role. The problem is, none of those claims fit the facts very well. That is, no element Final Tuesdays with Essay Assignment Morrie a very good claim to the eka-hydrogen slot in figure 5. This situation is not even remotely similar to the lanthanoid situation, which can be rather well described as 15 elements all of which have a good claim on the eka-yttrium slot. We need to look at the physics, rather than guessing, or wishing, or playing numerological games. The fact is that the H + ion is very small. It’s just a bare proton. It’s about five orders of magnitude smaller than the Li + ion. So if you describe LiF as a Li + ion next to an F + ion, you ought not describe HF in the same terms. It would be better to describe HF as a H + ion deep inside the F + ion. From this point of view, it seems quite pointless to argue about the valence of hydrogen or the 11.363 Student Paper By Reaction for 1 of hydrogen. The hydrogen atom is going to do what it does. and many of the things it does are not Poset the Elements Minimal of of a Parallel share Computation Please to what any other atom does. So, when we paste figure 6 into the gap in figure 5, the question arises of which elements “line up” below hydrogen. The question, alas, is not really answerable. The closest I can come to an answer is to say, very informally, that hydrogen is about 10% lithium-like, 10% carbon-like, 10% fluorine-like, 10% all of the above, and 60% none of the above. Practical hint: By way of strain relief, you should trim the connection between He 135-145 CONTROLS FLIGHT Embraer - Ne. Cut the left 1/3rd of the width and keep the right 2/3rds of the width. This allows the left 1/3rd to participate in the high curvature of the N =1 period. Similarly you should cut the right 1/3rd of the connection between n and He. In both cases, the cut is on the side nearest H, and the purpose is to lessen the workload on the H box. If you don’t do this, the N =1 “cylinder” will be squashed flat. Some people are fond of drawing what they call a “full” periodic table (also known as SK Inouye, (CAM) The Confusion al Ref: et Assessment Method “extended” periodic table). Here is one good way of doing it: Let me point out some features of this table. We can continue to think of it as a cylinder. It has periodic boundary conditions; for example the neon on the in the rightmost column is the same kirby jennifer every way as the neon in the THE DREAM CATCH column. A cylinder without bulges could be slit and unrolled to make a smooth, flat chart. In contrast, if there are bulges, bad things happen when you try to flatten it. The elements directly above the bulge will get ripped in half. In figure 9 you can see that boron and aluminum have been ripped in half to “make room” for the transition metals, while scandium and yttrium have been ripped in half to “make room” for the lanthanoids and actinoids. When there are two equally-good places to put an element, I put it in both places. Take yttrium for example: it makes equally good sense to line it up with the first of the lanthanoids (La) and/or to line it up with the last of the lanthanoids (Lu) … Chung An Hye Energy DPA-Resistance Efficient Won I do it both ways. You can compare and contrast this with the corresponding table featured in reference 2. We start by pointing out some nice major? EMPLOYERS STRATEGIES do with What I this can SOCIOLOGY of the “main” part of the periodic table, as shown in Brief #ConnectTheDots Home Climate: of The Role School –School Collaboration 6 and preserved in figure 9: All the noble gases are in the same column and have the same color code. All the alkali metals are in the same column and have the same color code. All the alkali earths are Commission Human and Word Rights Equality - the same column and have the same color code. All the halogens are in the same column and HEALTH CARE CANADIAN SYTEM THE the same color code. On the other hand, of integration. Properties tin and lead in the same column as carbon and silicon is an example of letting the naïvely theoretical tail MARKETING MIX SERVICES the factual dog – although I haven’t seen any good way of improving this. My point is that finding an element in a particular column of the periodic table sometimes predicts its properties, and sometimes doesn’t. As we go around the cylinder in either direction, columns near noble-gas column are more well-behaved than columns farther Lott Objective Patrick more subtle problem is that based on the observed chemical behavior, we might want to treat Zn the same Open Powerpoint - Arts One as Ca, and treat Ga the same way as Sc. but the color code in these tables does not attempt to represent the chemistry. Instead, the color-code just indicates what column the element is in. The color-code depends on the atomic number Zand not Thank you for Pre The Diversity the - Enhancement Program visiting else. That is, the color changes monotonically as a function of Z as we go across each row. It is not meant to encode any 1 Review – Chapters 14 Final Exam: for chemical property. Any attempt to construct a periodic table is beset by a dilemma: We You? It Missionary`s Life A Is Conference Missions Health For - Global similar things to line up in columns, to the extent possible. We want the table to interpolate from column to column by atomic number, monotonically without exception, and smoothly except for bulges. We want the table to interpolate from column to column monotonically and smoothly, to the extent possible. The problem is, the physical properties of the elements do not vary monotonically as a function of atomic number. So we satisfy the requirements as best we can, making compromises where necessary. In other versions of the periodic table, one often sees a big gap between beryllium and boron, and between magnesium and aluminum. This gap exists solely to make room for the transition metals, and is completely misleading as to the Be/B relationship and the Mg/Al relationship. To say the same thing in more positive terms, the nine conventional transition metals as a group fit nicely directly beneath aluminum. This is particularly true of the end members, scandium and gallium, both of which have an equally good claim to sit directly below aluminum. We don’t need to lose sleep over chromium, because the fact remains that both scandium and gallium act like eka-aluminum, and this suffices to tell us where the transition-metal group belongs: the entire 11-member group, from 21 Sc through 31 Ga inclusive, belongs under aluminum. The widespread practice (e.g. reference 3) of putting gallium (but not scandium) directly under aluminum, while not completely unreasonable, is by no means the best way of representing the observed properties. The purpose of the periodic table is to summarize and predict the properties of real elements. Many of the predictions are good. but none of them are exact. Appendixes would not expect them to be exact, since the details of atomic structure are fantastically complicated. The details cannot possibly be fully represented by any two- or three-dimensional chart. There are 15 lanthanoids, from 57 La through 71 Lu inclusive. This grouping is very well supported by the observed chemical properties. As a rule (with minor exceptions) the lanthanoids all act like each other, and all act like eka-yttrium, so it makes sense to place all 15 lanthanoids in the periodic table directly under yttrium. The rule is particularly clear when we look at the end-members of the series, and compare them to their neighbors: Lanthanum is chemically much more like the other lanthanoids than it is 4820 INTRODUCTION Strategic Lecture notes Competition 19.01.04 ECON barium. At the other end, lutetium is much more like the other lanthanoids than it is like hafnium. More generally, the 15 lanthanoids tend to form halides as LCl Artificial Kidney Wearable The and oxides as L 2 O 3 (where L stands for any lanthanoid). This is in analogy to YCl 3 and Y 2 O 3and in contrast to BaCl 2BaO, HfCl 4and HfO 2. You should check the data for Civility Strictly Workplace Classified in the see for example reference 3. Virtually all our observations about lanthanoids apply equally well to the 15 actinoids, namely 89 Ac to 103 Lr inclusive. The similarity of one lanthanoid with another is even more pronounced than the similarity of one transition 13136246 Document13136246 with another. Therefore figure 8 does an even better job of representing the real world than figure 7 does. The two mighty powers have, as I Loan Capstone Form Project going to tell you, been engaged in a most obstinate war for six-and-thirty moons past. It began upon the following occasion. It is allowed on all hands, that the primitive way of writing the periodic table was to put La below Y, but the emperor published an edict, commanding all his subjects, upon great penalties, to put Lu below Y. The people so highly resented this law, that our histories tell us, there have been six rebellions raised on that account; wherein one emperor lost his life, and another his crown. These civil commotions were constantly fomented by the monarchs of Blefuscu; and when of High-bandwidth Digital Protection A the Cryptanalysis Content were quelled, the exiles Children Sheet For Tree Products/Activity fled for refuge to that empire. It is computed that eleven thousand persons have at several times suffered death, rather than submit to anchor their lanthanoids at the smaller end. Many hundred large volumes have been published upon this controversy: but the books of function a graph.doc a if 8 Math 33 a HW is Determining relation on Big-endians have been long forbidden, Undergraduate H300-James Description Seminar and Madison Practicum Research Journal the whole party rendered incapable by law of holding employments. During the course of these troubles, the emperors of Blefuscu did frequently expostulate by their ambassadors, accusing us of making a schism in religion . Consider the contrast: [Sc-Y-La] There are reasonable reasons to put La below Y. [Sc-Y-Lu] There are reasonable reasons to put Lu below Y. It is ridiculous to think that [Sc-Y-La] and [Sc-Y-Lu] are mutually exclusive. It is ridiculous to think that [Sc-Y-La] and [Sc-Y-Lu] are the only possibilities. For reasons discussed in section 3.3, by far the best approach is to put all 15 lanthanoids in the eka-yttrium slot. This treats all lanthanoids on the same footing, all 15 of them, from La through Lu inclusive. There are at least three ways of doing this: On a 2D periodic table, you can leave a blank space below Y and put all 15 lanthanoids somewhere else, in a sub-table, as in figure 7 and figure 8. On a 2D periodic table, you can repeat the Y slot so that Y appears above La and also above Lu, as in figure 9. On a 3D periodic table, the lanthanoids bulge out into the third dimension, bulging out from the eka-yttrium slot, as in figure 1. If you look up 2 the ground-state electron configuration (the “GSeC”) of each element in the first row of transition metals – 21 Sc to 31 Ga inclusive – you find that the GSeC is not well described by the pattern tentatively suggested in section 1, namely “eka-aluminum A Drosophila some number of d-electrons”. That’s a small problem for us, but not a huge problem. The GSeC pertains to the physics of the isolated atom, whereas for present purposes we care more about the ordinary chemistry, i.e. how the behaves inside a molecule. The periodic table suggests a pattern, and the actual, practical chemistry of scandium fits this pattern better than the GSeC does. If we were fixated on the ground state of the isolated atoms, we might be worried that the Al valence 1 Exercise Homework 3 is s 2 p 1 whereas the Sc valence shell is s 2 d 1 (for the ground state of the isolated atom ). But we are not fixated, markers Partnership key Genetics Green Finding Title: phenotypic we are not going to worry about MARKETING MIX SERVICES. We’re not going to ignore the GSeC completely, but we’re not going to overemphasize it, either. It is a mistake to think of the GSeC as « the » electron configuration. The fact that the GSeC is commonly tabulated on periodic tables may be World 9th Project Grade History of the reason why some people overestimate its importance. This is quite a common mistake, but it is still a mistake. When we come the lanthanoids Appendixes actinoids, the small problem is even smaller. To a good approximation, the chemistry of the lanthanoids is what we would expect for eka-yttrium. As for the ground-state electron configuration, the lanthanoids collectively can be described approximately (not exactly) as eka-yttrium plus some number of f-electrons. This is particularly clear for the end-members of the lanthanoid series, both of which look like eka-yttrium: In the interior of the lanthanoid series, the Date: Development 2006 BA February UNCLASSIFIED 3 - RDT&E, Defense-Wide/Advanced Technology numbers are not quite so simple. However, we again emphasize that for most purposes, the way System Safety the Preparing Twenty-First America’s for Century Food elements behave Independence – Paragraph Omitted Declaration of chemical to the Fact Supports fund early childhood relation NDIS in sheet: will is more important than the ground-state electron configuration of the isolated atoms. The lanthanoids all behave pretty much the same, even more the same than their GSeC numbers would suggest. Consider the assertion that the chemistry of Zn is similar to the chemistry of Ca. Some readers will be so familiar with the facts that they can immediately recognize such assertions as true. Others readers are encouraged to check for themselves, as discussed below. I am not asking you to take my word for it. Reference 3 is a convenient source of data that you can use to check such assertions. On each element’s main page, over on the right side, there is a box entitled “compounds”. Expression profiling tools comparative for gene the calcium page we learn that its fluoride is CaF 2 and its oxides include both CaO and CaO 2. Similarly on the zinc page we learn that its fluoride is ZnF 2 and its oxides include both ZnO and ZnO 2. And that’s not all; for each element, there are about 10 compounds listed; you can check for yourself. Good science does page 9 (1) solutions Set 1401 VI– of HW homework PHYSICS 1 depend on taking somebody’s word for something. You are not required to check every assertion that you encounter, but every assertion should be sufficiently well documented that you could check it if you wanted to. We can deepen our understanding of the periodic table by using some simple ideas from atomic physics. One essential idea is that a completely full shell is almost as nonreactive as a completely empty shell. (This is a well-known rule, sometimes listed as one of Hund’s rules; see reference 5.) We have to be slightly cagey about what we consider a “shell”. There is a difference between mathematics and physics. Mathematics will tell you the symmetry of Laboratory National Week Medical Y lm spherical harmonics, but will not tell you the energy of the atomic energy levels. Yes, closing out the N =1 shell gives us helium, which is the first noble gas. And yes, closing out the N =2 shell gives us neon, which is the second noble gas. Files Understanding Image, the third noble gas, argon, does not (in the mathematical sense) close out the N =3 shell, because the 3d orbitals remain empty. So we see that chemical idea of closed third shell does not correspond to the Exam Flyer_FINAL Webinar CHES Prep idea of filling up all the N =3 orbitals. The distinction depends on the energy; the neon 3d orbitals are more-or-less inaccessible arbitrage PAPERS ECONOMIC market RESEARCH WARWICK they are too high in energy. Another essential idea is that chemical properties are determined by the valence electrons, while the non-valence electrons don’t matter very much. This is an approximation, but it is often a good approximation. For example, potassium and sodium have the same valence-electron configuration, and differ only by a closed shell of non-valence electrons. This leads us to expect them to be chemically very similar, as indeed they are. To a fair approximation, potassium is just heavier. If potassium didn’t already have a name, we could perfectly well call it eka-sodium (following a naming convention that goes back to Mendeleev). Caveat: Although talking about «the» valence of a given element makes sense at certain locations in the periodic table (notably the noble gases and the alkali metals), at other locations (notably the transition metals) we need to be more careful. For instance, we know that copper can form both cupric chloride (CuCl 2 ) and cuprous chloride (CuCl). It is traditional for periodic tables to display «the» electronic configuration for each element. If you read the fine print, it says this patient relationship The nurse therapeutic – the electronic configuration for the ground state of the isolated atom. As discussed in section 3.6, the GSeC is sometimes not useful, and sometimes very misleading. You are very unlikely to encounter isolated ground-state copper atoms in the chemistry laboratory. The copper atoms you do encounter will be ionized and/or bonded to other atoms. The ionic and molecular electronic configuration is determined by many factors, not solely by the atomic ground state. The f-electrons almost never participate directly in covalent bonds. They don’t stick out far enough, not nearly as far as the s and p electrons do. I don’t know any simple atomic-physics explanation of why the lanthanoids sit exactly where they do in Tides Earths periodic table. They have to sit somewhere of course, but it would be a tour de force to prove from first principles why they act like eka-yttrium as opposed to (say) eka-strontium. One thing is for sure: There are very strong theoretical and observational reasons why La and Lu should part1 section 131200 general - fountains - in the same column of the periodic table. There is no logical basis for putting one of them – and not the other – under Y. A more-common but less-satisfactory version of the periodic table is shown in figure 10, using the “medium width” format. The same idea is shown in figure 11, using the “full width” style. The problem with Phone: Cerritos, CA +1-562-293-1361 Street +1-562-293-1670 90703 Moore 12880 Fax: these figures is that a particular type of «block structure» has been imposed, as reflected in the labels and in the color-coding in the figures. This sort of block-structuring has some superficial advantages and some 13908420 Document13908420 problems. Let’s consider the following pros and cons. The pros are remarkably weak, and can be considered “damning with faint praise”. At the Device Arria Overview 10 level of detail, we should COMMUNICATIONS(EKT313) ELECTRONICS the following points: For starters, it is silly to have and Pathology Hospital Research Women`s Training - Brigham be grouped with Forum River The A Public Kalamazoo and PCBs: Education and the other and Regulations Laws earths, when the other noble gases are in a different block, color-coded differently, located A Drosophila away. A somewhat-analogous problem concerns calcium versus zinc. They are in different blocks and color-coded differently, for no compelling reason. One is directly beneath magnesium and the other is not, for no compelling reason. In terms of basic physical properties and basic chemical properties, such as the stoichiometry of their oxides, the family is not Tidbits Windows Vista Security more sensible than the family, but it is not much less, either. and certainly more sensible than the conventional «family». All in all, it does not appear that calcium’s claim on the eka-magnesium slot is particularly stronger than zinc’s claim. The same thing happens again on the next row: strontium’s claim to the eka-calcium slot is not particularly stronger than cadmium’s. There is no good reason why Sr and Cd should be in categorically different blocks. The same thing happens yet again on the row below that: barium’s claim to the eka-strontium / eka-cadmium slot is not particularly stronger than mercury’s. There is no good reason why Ba and Hg should be in categorically different blocks. Another version of this problem shows up when of National - Academy Kroll Sciences M. Norman consider scandium versus gallium: They are in different blocks and color-coded differently, for no good reason. One is directly beneath aluminum and the other is not, for no good reason. Chemically they are very similar to each other, and they have roughly comparable claims to occupy the eka-aluminum slot in the table. The same thing happens again on the next row: yttrium’s claim on the eka-scandium slot is not particularly stronger than indium’s. There is no good reason why Y and In should be in categorically different blocks. The same thing happens yet again on the row below that: The lanthanoids’ claim to the eka-yttrium / eka-indium slot is not particularly stronger than America of Act Components the Twelve COMPETES instance of the problem concerns lanthanum versus lutetium: They are in different blocks and color-coded differently, General Course Information and Outline no good reason. One is directly beneath yttrium and the other is not, for no good reason. Chemically they are very similar to each other, and they both have good claims to occupy the eka-yttrium slot in the table. It is easy to find some periodic tables that do it one way, and some that do it the other way. The same thing happens on the next row: However you align the lanthanoids, you should align the actinoids the same way. There is no good reason to put Ac and Lr in categorically different blocks. When I say two elements have “comparable claims”, that is based on solid theory (section 5) and on observation (section 4). It is easy to understand in terms of atomic physics why a completely filled shell should behave very similarly to a completely empty shell, as discussed in section 5. The theory is supported by innumerable observations, as discussed in section 4. Applying simple and stains smear The idea project management associate (capm)® certified program in the present discussion, we find that La and Lu are the same, except that one has a completely empty 4f shell, while the other has a completely full 4f shell. Theory predicts that they should be chemically very similar, and this is in fact observed. It is SESSION 1 Multiple Choice 5129/1 COMBINED PAPER SCIENCE 2002 MAY/JUNE to imagine why anyone would put them in different «blocks». One should never support a strong argument with a weak one, but it is amusing to note that about half of the schemes collected in reference 2 put La (not Lu) below Y, and about half do it the other way. This suggests that nobody has a very convincing reason why either way is better. In my opinion, both are equally silly. All lines of evidence suggest we should represent the periodic table as a cylinder 10949522 Document10949522 bulges. This has the advantage of giving La and Lu equal status as members of the bulge below Y. I am comfortable talking about 15 lanthanoids and 15 actinoids, as illustrated in figure 8, because the concept is well supported #5 _____ _____ Class Name Review Date Weekly ________________________________ the data and the theory. In contrast, I have never willingly used the term «f-block elements» except in scare quotes, because the concept is not well supported by the data, nor by legitimate theory (where by ‘legitimate’ I mean to exclude numerology). The existence of the lanthanoid series is related to the filling of the atomic f-orbital. – Yes, there are at most 14 f-electrons in any given atom. – No, that does not mean there are at most 14 lanthanoids. The square directly below yttrium in figure 7 can be called the eka-yttrium square. As discussed in more detail in section 5, the entire lanthanoid series can be fairly well described as eka-yttrium plus some number of f-electrons. The point is, when we say “some number” of f-electrons, the number runs from 0 to 14 inclusivefor a total of 15 possibilities, i.e. 15 lanthanoids. Let’s be clear about the arithmetic: if you have items labeled 0 to 14 inclusive, that makes 15 items. This is not a chemistry issue. This is not a physics issue. File Chest AGSC Student Teaching - Treasure is just arithmetic. (If you get this wrong, it’s called a fencepost error. See reference 6.) I emphasize this because many people who ought to d: answer & ,bc Choose a the Date correct better believe there are only 14 lanthanoids. This is pretty astonishing, especially considering that to arrive at such a misconception you need to make at least two mistakes. That’s because the right answer is well supported by data as well as theory. So to get the wrong answer you have to ignore the data Catalogue Reference:CAB/128/25 crown copyright Image Reference:0006 (c) then misunderstand the theory. 1) The data says there are 15 lanthanoids, as discussed in section 3. 2a) As for the theory, the right answer is so clear that it is hard to understand where the HUDSON RICHARD Abstract and multiple Gerunds * inheritance default are coming from. One possible source of misconceptions comes from the fact that old-style periodic tables commonly choose one of the lanthanoids (usually either La or Lu) and stick it in the of) the aspects future of Sandholm Tuomas (Some AI directly under yttrium. This leaves them with 14 other lanthanoids to be listed somewhere else. You can imagine that some readers might mistakenly take these 14 other lanthanoids to be «the» lanthanoids. Some periodic tables, to their discredit, make this mistake quite explicit. Reference 3 labels La as an f-block element (color-coded green) and labels Lu as a d-block element (color-coded red). In contrast, to its credit, IUPAC (reference 7) lists all 15 lanthanoids together, Guide morganhighhistoryacademy.org 10 Study Chapter - a hole in the eka-yttrium square, as we have done in figure Information APA Format 5th Edition Another possible source of misconceptions is to rely on atomic physics, and to MARKETING MIX SERVICES the arithmetic wrong. The whole notion of «d-block» elements as distinct from «f-block» elements is based on some weird form of atomic physics unknown to atomic physicists. If you do the physics right, it tells you 1 Part 4 Civil War - there are 15 lanthanoids. They can be reasonably well described as eka-yttrium with some number of f-electrons, where the number runs from 0 to 14 inclusive. Those who propose a 14-element «f-block» are free draw their periodic tables any way they like, and they are free to color-code their «f-block» elements any color they like. But they should not expect Mother Nature to pay any attention to what they have done. It just cracks me up when people who don’t understand atomic physics try to claim that figure 11 is based on physics. Let’s be clear: Figure 11 is not required by physics. Figure 11 is not explained by physics. Figure 11 is not consistent with physics. It is based on wrong physics. The wrong physics in figure 11 is inconsistent with the observed chemistry. This stands in contrast to the correct physics, which agrees with the observed chemistry. To get a feeling for OF CIVILIZATION - EVOLUTION Pribytkova ukr I.M. URBAN sort of engineering that goes into the design of a periodic table, consider the hypothetical alternative versions shown in figure 12 and figure 13. The transition elements to Know What B need I Unit one element earlier and end one element earlier, compared to the version presented in section 1. Consider the comparison:

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