What is Elements: Definition and 1000 Discussions

Éléments is a French bi-monthly magazine launched in September 1973 and associated with the Nouvelle Droite.
With a social and European inspiration, the magazine promotes a critical vision of liberal modernity on topics such as localism, ecology, respect for cultural diversity and the defence of European identity.

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  1. I

    First ionization energy of group 1 and group 2 elements

    The first ionization energy decreases between group 5 and group 6 due to the repulsion between the electrons in the p orbital. Although I understand that the effective nuclear charge increases between group 1 and group 2 elements, why isn't this the case between group 1 and group 2 elements...
  2. Z

    Are there any elements found in space but not at all on Earth?

    Are there any elements found in space but not on Earth?
  3. R

    How Many Natural Elements Are There?

    I always thought there were 92 natural elements, ending with atomic number 92 Uranium. However, I read where 94 are considered natural, to wit, 93 Neptunium and 94 Plutonium. Yet, the latter two need to be synthetically prepared. How can they be considered natural? Was 94 always the accepted...
  4. sophiatev

    I Invariance of Diff. Line Elems. in Hartle's Gravity: Intro to GR

    In Hartle's book Gravity: An Introduction to Einstein's General Relativity he spends chapter 2 discussing some basic aspects of differential geometry. For example, he derives the expression for a differential line element in 2D Euclidean space: dS^2 = (dx)^2 + (dy)^2 in Cartesian coordinates...
  5. F

    A Calculating Orbital Trajectories for Spaceflight Simulators

    Hi! Basically I am developing a spaceflight simulator specifically for the space shuttle. Coding the Shuttles Systems etc. is not actually the hardest part, as I had thought before. The real problem is the physics engine :confused: The main problem I have is, that with all the Equations for...
  6. S

    I Set Theory - the equivalence relation on elements

    According to https://plato.stanford.edu/entries/zermelo-set-theory/ , Zermelo (translated) said: I don't know if that quote is part of his formal presentation. It does raise the question of whether set theory must formally assume that there exists an equivalence relation on "elements" of...
  7. Kaushik

    General electronic configuration of the d and f block elements

    Is it ##(n-1)d^{1->10}ns^2 \ or \ (n-1)d^{1->10}ns^{0->2}## ? My textbook says it is the latter. But I feel like it should be the former. Moreover, period 6 and 7 has the presence of f-orbitals. So adding## (n-2)f^{0->14}## would make it more general. Isn't it? And also what about the f-block...
  8. J

    I How Are Heavy Elements Distributed?

    Hello, I was just pondering how certain heavy elements group together in the new bodies that they form. Ex. that got me thinking: So gold would have been created one way thru a supernova right? Say this supernova spread some gold dust all over the cosmos. 1. Why whenever a body such as...
  9. B

    Alien Worlds.... Alien Elements?

    The perodic table we learn in school. All the stuff on it is found on Earth, and some of it (not all of it) we can find on other worlds. So it got me thinking, what about alien scifi worlds? Unobtanium is a common scifi trope, and all too often scifi humans envy aliens having unobtanium. But...
  10. H

    Question about the bond MO's for diatomic early 2nd period elements

    So this question is about the bond molecular orbital diagrams for elements in the 2nd period, before O. When the diatomic bond forms, the two pi 2p* orbitals are shown lower in energy than the sigma 2p*, uptil we get to O2. I want to understand why this is? From what I know, a sigma bond...
  11. Luminescent

    What elements account for these absorption lines seen?

  12. Monoxdifly

    MHB [ASK] Determinant of a Matrix with Polynomial Elements

    Help me if what I have done so far can be simplified further.
  13. evinda

    MHB How to Sort Elements of a Matrix in O(n) Time Complexity?

    Hello! (Wave) Let a matrix with $n$ integers in the interval $[1,100]$. I want to write an algorithm that sorts the elements of the matrix in $O(n)$. [Hint: Count and use the number of times that each number appears] I have thought the following: We create a matrix with $100$ entries. If the...
  14. M

    MATLAB How can I efficiently extract elements from a large cell in MATLAB?

    Hi PF! I have a cell 1 X 5001. Each component within is a double matrix of different sizes, approximately 100 X 3. The entire cell is called a. Then when trying to extract component (1,2) from each of the 5001 matrices I type a{:}(1,2), but upon executing this MATLAB complains "Expected one...
  15. Jason Bennett

    Lorentz algebra elements in an operator representation

    1) Likely an Einstein summation confusion. Consider Lorentz transformation's defined in the following matter: Please see image [2] below. I aim to consider the product L^0{}_0(\Lambda_1\Lambda_2). Consider the following notation L^\mu{}_\nu(\Lambda_i) = L_i{}^\mu{}_\nu. How then, does...
  16. Adrian Tudini

    Computer code that handles the periodic table of elements

    Hi guys When I ran the Chemical Equilibrium Code from NASA (grc.nasa.gov) to predict the products of a chemical reaction and their concentrations, it says it does not handle certain elements in the database from the periodic table. Is there a computer code that predicts the products of a...
  17. P

    Heating of elements with laser light

    One of the emission lines of iron is 404nm, would iron absorb the heat from a blue laser and not copper? Not a student, just an old curious guy. Thanks, Philip
  18. F

    I Fissionable elements for Fission

    Hello, Quick question: in fission, which is a nuclear reaction, a large element is hit with neutrons and broken/split into two smaller elements while lots of energy is released. Does the starting element, which must be large in size (like uranium-235 or plutonium-239) need to be an element that...
  19. Euge

    MHB POTW: Show Odd No. of Elements $g \in G$ for which $g^3 = 1$

    Here is this week's POTW: ----- Show that if $G$ is a finite group, then there are an odd number of elements $g\in G$ for which $g^3 = 1$. ----- Remember to read the https://mathhelpboards.com/showthread.php?772-Problem-of-the-Week-%28POTW%29-Procedure-and-Guidelines to find out how to...
  20. christang_1023

    I What is the addition law for probability with multiple elements?

    The additional law with two elements can be expressed $$P(A\cup B)=P(A)+P(B)-P(A\cap B)$$, while the law with three elements can be $$P(A\cup B\cup C)=P(A)+P(B)+P(C)-P(A\cap B)-P(B\cap C)-P(A\cap C)+P(A\cap B\cap C)$$ Now I wonder if there is the more general form of addition law, which applies...
  21. A

    Naturally Occurring Elements: the latest version

    What exactly is a naturally occurring element? How many naturally occurring elements has been observed? -the Latest Version! Would you please tell me the exact atomic no range of such elements (with exceptions)? I would be really grateful if anyone could answer my questions. (Based on...
  22. Aresofthesea

    Need a way to electronically detect elements

    I recently came up with the idea of the OMBARD (Object Memory Based Atom Reassembly Device). Yes, I know, it's a mouthful. Basically, it analyses the complete atomic structure of an object and stores the data. It has a storage unit filled with extremely dense matter. It can then destroy the...
  23. Moni

    A Ascending Order of the Sums of the Elements of the Sub(multi)set of MultiSet

    Summary: Generating Subsets of a Multiset in Ascending Order of the Sums of the Elements of the Sub(multi)set I am trying to come up with an algorithm where you can generate combination from a set in a order such that their sums are in increasing order. This set has to be a multiset i.e...
  24. Max Kovalevich

    Transform the periodic table of chemical elements.

    Summary: Transform the periodic table of chemical elements (periodic table) into a universal way of storing and transmitting information using spectral analysis. I propose a concept in which the basis for working with information (conservation, transmission in networks) is to use spectral...
  25. A

    B Tau catalyzed super heavy elements

    Today I was reading about super heavy elements and was wondering if a tau lepton could be used to synthesize SHE's? As a side note, as relativity is applied to hypothetical SHE's Would you not end in a black hole as a limit to possible elements? and maybe a way to calculate and predict quantum...
  26. A

    "Assembly" of elements of different dimensionalities (1-D, 2-D)

    I am currently working on a problem which involves both 1D and 2D elements. I know that these elements have different degrees of freedom at a node and, therefore, the procedure of assembly of elements will different from a purely 1D or a purely 2D mesh. I don't know the rest of the details. Any...
  27. lastItem

    I Calculating Momentum Operator Matrix Elements from <φ|dH/dkx|ψ>

    Is there a relationship between the momentum operator matrix elements and the following: <φ|dH/dkx|ψ> where kx is the Bloch wave number such that if I have the latter calculated for the x direction as a matrix, I can get the momentum operator matrix elements from it?
  28. Khatti

    Handwavium and other precious elements

    The next question is a little more esoteric: is it likely that there are any elements out there that we haven't discovered yet? Does anyone have any thoughts on how Dark Matter might figure into the question I've asked? Again, the mining world idea applies. Feel free to speculate on this...
  29. Khatti

    Star ship building: What elements are needed to build the ship?

    Okay I have two questions that I plan to post separately. The first question is simple: what elements will be needed to further space travel in the future? Does anyone care to comment on what base elements would be necessary to build the starship Enterprise? I should explain the reason why I'm...
  30. maistral

    A Deriving the FEA formulation using triangular elements

    Hi, it's been a while since I last posted. Anyway, so I went through the trouble of enrolling in two finite element analyses classes and yet, they still don't teach how the 2D formulation has been made. I'll list the things that 'I know' already to get some things clear. I know how to derive...
  31. I

    List of all elements found in ribosomes?

    Hello, I am trying to find a breakdown of all the elements that a ribosome complex would contain. Any feedback appreciated!
  32. A

    The Definition Of Chemical Elements

    I don't get it - the definition of a chemical element is: "Cannot be chemically interconverted or broken down into simpler substances" -- But isn't every atom of an element made up of further sub-atomic particles, and atoms can be then broken apart, etc...? Also, how did people tell the...
  33. jk22

    B Composition of elements of SO(4)

    It's a beginner's question : if I consider compositions of Givens' rotations, how many should I combine to obtain the whole group, since those don't commute and hence their order is important ? Is it 6 ?
  34. jfizzix

    I Are no chemical elements truly stable?

    I recently learned that Bismuth is actually radioactive with its longest lived isotope having a half-life of about 20 quintillion years. (For source, see: https://www.nature.com/articles/nature01541) As a very basic question, what determines whether an element/isotope will be radioactive? Is...
  35. mvgmonteiro

    Maximum determinant of matrix with only 1 and -1 elements?

    1. The problem statement: Find out the maximum determinant of a matrix nxn which have just 1 and -1 elements. 2. The attempt at a solution: I have tried for 2x2 and 3x3 matrices and so generalizing for nxn matrices. But I can’t figure out any pattern or something like that. Also, I barely know...
  36. H

    How many Peltier elements can I use in my power outlet?

    Hi! I want to build some cooling with peltier elements. At home I get 230V from power outlet and the maximum allowed power consumption is 15A. However, when I look at peltier elements at online store I notice that amps go up fast. Like some 12V 180W peltier is already 15A. Does this mean that I...
  37. M

    MHB Sum of basis elements form a basis

    Hey! :o Let $V$ be a vector space. Let $b_1, \ldots , b_n\in V$ and let $\displaystyle{b_k':=\sum_{i=1}^kb_i}$ for $k=1, \ldots , n$. I want to show that $\{b_1, \ldots , b_n\}$ is a basis of $V$ iff $\{b_1', \ldots , b_n'\}$ is a basis of $V$. I have done the following: Let $B:=\{b_1...
  38. M

    Low voltage across low resistance for heating elements

    I am planning some low power heating devices in the 10 - 20 watt range and have been considering the usual high resistance alloys: nichrome, kanthal, and stainless steels (304, 316, 630). I have noticed that all of these materials are expensive. Is there some reason I could not just use steel...
  39. karush

    MHB Describes elements of D_5 using SAGE

    Describes the elements of $D_5$ ok I think the elements of $D_5$ are $$R_0\quad R_{72} \quad R_{144} \quad R_{216} \quad R_{288} \quad F_1 \quad F_2 \quad F_3 \quad F_4 \quad F_5$$ ok from this was going to make a cayley table but was wondering if anybody know how to do this with SAGE...
  40. mnb96

    A Representation of elements of the Grassmannian space

    Hi, I am studying some material related to Grassmannians and in particular how to represent k-subspaces of ℝn as "points" in another space. I think understood the general idea behind the Plücker embedding, however, I recently came across another type of embedding (the "Projection embedding")...
  41. T

    I Images of elements in a group homomorphism

    Why does the image of elements in a homomorphism depend on the image of 1? Why not the other generators?
  42. Mr Davis 97

    Determining elements in Aut(D_8)

    Homework Statement Find all of the elements in ##\operatorname{Aut}(D_8)##. Homework EquationsThe Attempt at a Solution I am trying to come with a repeatable procedure for finding automorphisms of groups with presentations. I'm taking ##D_8## as a good example. Here is how I would like to...
  43. Mr Davis 97

    Aut(D_12) Elements & Inner Automorphisms: Dihedral Group with 12 Elements

    Homework Statement Find all the elements of ##\operatorname{Aut}(D_{12})##. Which elements are inner automorphisms? Note: ##D_{12}## is the dihedral group with ##12## elements. Homework EquationsThe Attempt at a Solution I'm not really sure how to approach this. What I do know is that...
  44. H

    MHB Question on subgroup and order of the elements

    Let G be the group of symmetries (including flips) of the regular heptagon (7-gon). As usual, we regard the elements of G as permutations of the set of vertex labels; thus, G ≤ S7. (a) Let σ denote the rotation of the 7-gon that takes the vertex 1 to the vertex 2. Write down the cyclic...
  45. karush

    MHB 412.42 - Finding elements in S_3

    In $S_3$, find elements α and β such that |α| = 2,|β| = 2, and |αβ| = 3
  46. karush

    MHB -412.4.2 list elements and subgroups oa Z_30

    $\tiny{412.4.2}$ (a) List the elements of the subgroups $\langle 20\rangle $ and $\langle 10\rangle $ in $\Bbb{Z}_{30}$. (b) Let $a$ be a group element of order 30. (c) List the elements of the subgroups $\langle a^{20}\rangle $ and $\langle a^{10}\rangle $. should be easy ... just never did...
  47. Eclair_de_XII

    How many elements can be in an event space with two events?

    Homework Statement "Do there exist any event spaces with just six elements?" Homework EquationsThe Attempt at a Solution Suppose ##F_1## is an event space with a non-trivial event ##A##. Then ##F_1=\{∅,A,A^c,Ω\}##. So ##inf(|F_1|) = 4##, since if you remove any of these events, ##F_1## is no...
  48. karush

    MHB Orders of Elements in Groups $$\Bbb{Z}_{12}, U(10), U(12), D4$$

    nmh{909} For each group in the following list, $$ \Bbb{Z}_{12}, \qquad U(10)\qquad U(12) \qquad D4 $$ (a) find the order of the group $$|\Bbb{Z}_{12}|=12$$ (b) the order of each element in the group.ok the eq I think we are supposed to use is $$\textit{ if } o(g)=n \textit{ then }...
  49. Mr Davis 97

    Elements of Aut(Z/4Z) and their Inclusion in Inn(Z/4Z)

    Homework Statement Find, with justification, all the elements of ##\operatorname{Aut} (\mathbb{Z}/4\mathbb{Z})##. Which ones are in ##\operatorname{Inn} (\mathbb{Z} / 4\mathbb{Z})##? Homework EquationsThe Attempt at a Solution First we note that ##\operatorname{id}_{\mathbb{Z} / 4\mathbb{Z}}...
  50. Math Amateur

    I Primitive Elements and Free Modules .... ....

    I am reading Paul E. Bland's book, "Rings and Their Modules". I am focused on Section 4.3: Modules Over Principal Ideal Domains ... and I need some help in order to fully understand the proof of Proposition 4.3.14 ... ... Proposition 4.3.14 reads as follows: In the above proof by Bland we read...
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