Elements Definition and 984 Threads

Which elements "travel in pairs"? This isn't exactly "homework help", just something that's been on my mind for a while. I know that when writing chlorine, oxygen and hydrogen by itself, you need to add a two. Why is this so? And also, what other elements "travel in pairs"?

Hi, can someone please explain how to find the hybridisation when elements of the d-block are involved? For, example.. What is the hybridisation undergone by Fe in Fe(CN)2??

What element will react with crystalline causing it to lose it's organized pattern.

The Range Of Half-lives Of Different Radioactive Elements Is From_______ A)hours To Years B)hours To Weeks C)days To Months D)seconds To Billions Of Years E)days To Weeks

case 1)in finite element analysis of structures using simple rod elements we do the stiffness matrix and then find the displacements from loads and constraints case 2)finite element method is a technique for solving partial differential equations. In the case1 what is the partial...

can anyone help me with the following problem: I have been asked to estimate the rise in temperature in the salt in a final storage containing spent HTR-fuel elements in a time span of 100 years. Given the following data: Average heat flux 10 W/m; Heat capacity of salt 0.9 kJ/kg.K; density of...

This is question 53\gamma. Given a group G of transformations that acts on X... and a subgroup of G, Go (g * x = x for all x for each g in Go), show that the quotient group G/Go acts effectively on X. A group G "acts effectively" on X, if g * x = x for all x implies that g = e, where g is a...

I saw this problem in a book: calculate the sum of the elements of the U4 set. The answer is 0, the elements of the sets being: 1, i, -1, -i. My questions is: what's the U set? :confused:

Which 2 groups of substances below contain 1 element, 1 compound and 1 mixture? pick 2 groups. A.) Gold, sodium chloride, steel B.) oxygen, iodine, air C.) methane, iron(III)chloride, sea-water D.) Helium, carbon(IV) oxide, mixed dessert E.) Bronze, stainless steel, nitrogen(IV)oxide i...

Which of the following statements are CORRECT, concerning any elements in Group VI of the periodic table? pick out 3 CORRECT statements. A.) It has 6 valence electrons. B.) It has 6 electron shells. C.) It can form an ion of charge -2. D.) It has valency value of 2. E.) It will lose 2...

The Janet Periodic Table of Elements (1929) seems more "consistent" than the modern form. The location of any element (row, column) is directly related to the quantum numbers of the most significant electron of the element. Please see; http://ca.geocities.com/chemguy777/index.htm

Element A has a half-life of T_{1} and decays into element B, which has a half-life of T_{2} , while T_{2}<T_{1} . When is the mass of element B the greatest? (i.e. after how many doublings?) I have been trying to derive a formula to calculate this, but have so far been unsuccessful.

Name the following substances. a) [Cu(Cl[SIZE="1"]4]2- - tetrachloridecopper(II) ion b) Ag(NH[SIZE="1"]3)2+ - diamminesilver ion c) Cu(NH[SIZE="1"]3)[SIZE="1"]4SO[SIZE="1"]4 - tetraamminecoppersulfate (or tetraamminecopper(II) sulfate) d)...

i'm referring to this:http://aleph0.clarku.edu/~djoyce/java/elements/bookIX/propIX36.html does someone know if there's on the web another proof of this proposition, perhaps in a more readerable way. (i don't like to read also the geometrical approach and sliding through the links to the other...

Hey, I read about arbitrary elements sometime ago. Could anybody tell me what affects the values of these? And I also read that some say that the values of these are fine-tuned by the Creator. What is the general take on that?

Newbie here! Can anybody help me about the applications based on basic circuit elements like Resistors, Inductors & Capacitors! and where can I get 2 see the pictures of these elements:frown: sorry once again ... I don't know anything .. I AM A NEWBIE Want to learn :smile:

My list is this. 1) Oxygen with 51% 2) Silicon with 25% 3) Aluminium with 7% 4) Others I am not sure of these because I found them on the web and every site is different. I want to make sure so please anyone with Information post. Thanks :)

17th Century Copy of "Elements" I found an actual 16th century (or so the seller claims, but it matches up with what I've read about, i.e., only 6 books translated, plus 11-12. etc.) copy of a translation of Euclid's "Elements". I'm very tempted to buy it, but I want to know if it's rare. This...

I have a few questions: can heavier elements be made from lighter ones through breeding? Do unstable isotopes of light elements (lighter than lead) give off enough enough energy , when bombarded with nuetrons, to pruduce a coniderable amount of energy? What determines an isotopes critical mass?

Is the the following definition correct? Two elements a and b of a group G are said to be CONJUGATE if there exists g in G such that a=gbg^{-1}. For instance, show that all elements in the symmetric group S5 of order 6 conjugate.

I have already talked about this a little, but I have some more questions. Do transition elements obey the Octet rule? Also can you draw lious dot diagrams for them. It does not seem like you can, but I would like to know why. Also is Manganese the most stable transition element along with...

When calculating powers of cycles, are there any easy steps to use in doing so? I mean...is there a typical relationship when calculating (123)^n? Also, is it safe to say that a ceratin n-cycle should have order n or n-1? I guess any explanation of orders for group elements would be...

Which element in each of the following sets would you expect to have the highest second ionization energy? How do I figure this out? a. Na, Mg, Al b. Na, K, Fe c. Li, Be, Mg Can you help me? Thanks

Will on spring break earlier this year my dad informed me of a physicist who had recently passed away and who was responsible for detecting that all elements up to carbon(?) are formed in supernova. I have had a hard time searching for information on this man and his work and was wondering if...

Hi. On a general discussion forum, we were debating wether gold could be obtained from iron; I argued that this is possible, since we are at the moment recreating, in accelerators, even harsher conditions that those necessary for the creation of gold (i.e. those of a supernova core collapse). A...

i didn't know where to put this. can anyone tell me about any site from where i can download Euclid's "Elements" for free? thanks in advance.

Is there any cosmological observation that would suggest that once a star goes nova that its elements will not be recycled into another star, planet what ever ?

Hi! I'm having trouble answering some questions on a lab I did in class. Any help at all would be greatly appreciated! The purpose of the experiemt was to test the differences between pure substances (elements, compounds) and mixtures. If the procedure would help, here it is: 1. Mix equal...

Hello everyone, every row operation I make now is taking out the 0's i just made, any ideas on what I can do from here? Here is my work: http://img201.imageshack.us/img201/5573/lastscan2ah.jpg Also I was confused on how this works, my professor did an example: 3x+2y+z = 8; x = a y =...

Here is what the problem states. The most common elements found in organic compounds usualy bond covalently in the same fashion. This consistent bonding pattern or valence may be designated by an integer. For each of the following elements indicate its customary valence. Valence=number of...

All right, before reading this, please understand that I am only in my second year of study in high school. Bear with me... When looking at the activity series or metals and comparing it to the electronegativity and ionization energies of the elements, I noticed something quite interesting...

Hi everyone, My latest acquisition is an 8"-dobsonian mounted telescope, and I thought I'd try a bit of asteroid observing. What I would like to do is record the asteroid's position over the course of several observations and as a mathematical exercise, calculate its orbit. I know how to use to...

I found in a text that had this question. why should F, n row 2, be more reactive than iodine, in row 5, while Li, in row 2, is less reactive than Rb, in row 5? BUT this does not agree with this text http://richardbowles.tripod.com/chemistry/reactivity/reactivity.htm as it is more...

I remember hearing somewhere that one of the reasons people are trying to make elements which high atomic numbers is to see if they can be made to have long half-lives, such as uranium. In effect, they're virtually stable. However, I don't see how that can be. Here's why. Suppose element...

All elements are/ were made in stars, correct? Why is Earth predominated by certain elements and not by others? Does the composition of elements of other planets in our system differ from earth? If so, why?

Show that if G is a finite group of even order, then G has an odd number of elements of order 2. I'd appreciate a tip or two. I really don't see how the order of the elements of a group is linked to the order of that group.

Hello all, I'm re-learning chemistry on my own and have a quick question that I can't find the answer to in my book. Its about writing formulas. For example, aluminum chloride. I know that Al has a valence number of +3, and I know that Cl has a valence number of -1. So applying the...

Do you know any free software to draw elements or simulate chemical reactions ? I like the free ones :biggrin: Thankyou

I have encountered this set problem that seems simple enough at first glance, but I'm pretty ignorant about formal set theory and unsure of the rules. As I encountered it, this is how it was written: For any set S let P(S) denote all subsets of S. For example S={1,2} Then P(S)= {Ø, {1}...

Hi, I'm studying my astronomy course at the moment and i have question about the r- and s-process. As I understand it, in the r-process, the time between capturing two neutrons is shorter than the averge beta decay half life, right? So I'm guessing there have to be a lot of neutrons around for...

hi all, I am new here so if i break any rules please correct me er I am puzzled over an assignment and have no idea how to search for it, the question ask for the elements that was used to make semiconductor componets before it was replaced by silicon.. please help..a site help would do just...

Hello guys, I am following the chapter about multiple Riemann integrals in Apostol's Mathematical Analysis. Theorem 14.11 says this (I translate from spanish to english): "Let S be a Jordan measurable set. Let the function f be defined and bounded in S. Then f is Riemann integrable if and...

I'm looking for a trigonometry book that is rigorous, concise, insightful, etc. Something along the lines of Euclid's Elements, Spivak's Calculus, Rudin's Principles. I understand it's usually taught at the high school or college freshman level, but I'd like a book that someone who already knows...

1) why is the element fluorine added to tap water? 2) what element is believed to give lo.a moon of Jupiter its distinctive colour 4)what element was used to make semiconductor components before being replacedby silicon 5)where is triton found, please elaborate on it thanks kaluence

Hi, This time around I need to prove that a finite group of order 10 must contain an element of order 2 and an element of order 5. If the group is cyclic then this is trivial. So assuming the group is not cyclic, it's easy to show that there exists an element of order 2 in the group. And...

Is oxygen gas a chemical element? Is oxygen atom a chemical element? The oxygen element in the periodic table actually refers to an oxygen atom or oxygen gas that exist naturally in our surrounding air/atmosphere? Thanks to anyone that help and try to explain.

if a group of order 2p ( p prime) is abelian...then does it have exactly one element of order 2 ?? if a group is non abelian...i could figure out that there are p elements of order 2. but the abelian case is a bit confusing... also..is it like...any group of order 2p has an element of order p...

Hi, I've been having trouble erasing elements from a <vector> (that is from the STL of C++) See I declared 2 vectors V and S, V contains let's say all the elements, while S is a solution set which contains some elements that are classified... well yeah... I need to create V-S which is a...

A fuel cell runs off hydrogen and oxgen, would these elements be considered as biofuels? Is natural gas a biofuel?

Here’s an interesting question… Let R be a commutative ring and ‘a’ an element in R. If the principal ideal Ra is a maximal ideal of R then show that ‘a’ is an irreducible element. If a is prime, this is pretty obvious…if a is not prime, then we say a= bc for some b,c in R. Now we need to show...