Elements Definition and 984 Threads

I was reading the Exotic baryons page on Wikipedia and a cited source said that Ray Kurzweil, renowned Futurist said that at the end of the 21st century, we could use femtotechnology to create new chemical elements from exotic baryons that could create a new periodic table of elements. Here is...

I've written out the half reaction 8e- + 9H+ + SO42- = HS- + 4H2O and I know the logK = 4.25 (that's the constant mentioned in the prompt) I've written out the equilibrium statement of 10^4.25 = ([x^1/8]*[H2O^1/2])/([10x^1/8]*[e-]*[(10^-8.2)^9/8] However, from there, it seems like I have two...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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?

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...

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...

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...

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

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...

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 ?

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...

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...

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...

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...

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...

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...

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")...

Why does the image of elements in a homomorphism depend on the image of 1? Why not the other generators?

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...

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...

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...

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

$\tiny{412.4.2}$ (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...

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...

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 }...