What is Atom: Definition and 999 Discussions

The name Atom applies to a pair of related Web standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol (AtomPub or APP) is a simple HTTP-based protocol for creating and updating web resources.Web feeds allow software programs to check for updates published on a website. To provide a web feed, the site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by programs that use it, like websites that syndicate content from the feed, or by feed reader programs that allow internet users to subscribe to feeds and view their content.
A feed contains entries, which may be headlines, full-text articles, excerpts, summaries or links to content on a website along with various metadata.
The Atom format was developed as an alternative to RSS. Ben Trott, an advocate of the new format that became Atom, believed that RSS had limitations and flaws—such as lack of on-going innovation and its necessity to remain backward compatible—and that there were advantages to a fresh design.Proponents of the new format formed the IETF Atom Publishing Format and Protocol Workgroup. The Atom Syndication Format was published as an IETF proposed standard in RFC 4287 (December 2005), and the Atom Publishing Protocol was published as RFC 5023 (October 2007).

View More On Wikipedia.org
Recent contents Top users
  1. L

    What remains of an atom is ripped apart?

    http://hubblesite.org/hubble_discoveries/dark_energy/de-fate_of_the_universe.php "With dark energy, the fate of the universe might go well beyond the Big Chill. In the strangest and most speculative scenario, as the universe expands ever faster, all of gravity's work will be undone. Clusters...
  2. V

    How many electrons in the ground state of a Hg atom

    How many electrons in the ground state of a Hg atom can have the quantum number ml = +1? The way I am trying to figure this out is as follows.. Electron configuration for HG is.. [Xe]6s^2 5d^10 n=6 l : ml 0: 0 1: -1,0,1 2: -2,-1,0,1,2 3 -3,-2,-1,0,1,2,3 4 -4,-3,-2,-1,0,1,2,3,4...
  3. G

    Volume Effect of the Proton in Hydrogen Atom

    This Prob is from Shankar, 17.2.3 "we assumed that the proton is a point charge e. If the proton is a uniformly dense charge distribution of radius R, the interaction is modified as V(r)= -2(e)^2/(2R) + (er)^2/(2(R)^3) r<R = -e^2/r r>R Calculate 1st Order shift in the ground-state...
  4. C

    Why Do Helium Atom Energy Levels Split in Different Interaction Scenarios?

    Homework Statement I have having difficulty explaining the splitting of helium atom energy levels for three different cases: 1)Coulomb interaction is ignored 2)Coulomb interaction is present but exchange interaction is neglected 3)Coulomb and exchange interactions are present The Attempt...
  5. L

    Wavelength of a laser exciting H atom from n =2 to n = 5

    1. A monochromatic laser is exciting hydrogen atoms from the n = 2 state to the n = 5 state. What is the wavelength of the laser? 2. frequency = f = delta E / h lambda = c/f 3. First, is the following approach valid: I find delta E by computing E5 - E2, where En = n2h2/8mL2...
  6. C

    Atom Shapes: Visualizing Electron Clouds

    im having a little trouble trying to picture an atom in my head with accurate electron cloud designee and shape can someone give me some pictures or a site that might help. every picture i ever see of an atom is with the electron orbital in curricular shapes but i know there is a wide eray of...
  7. H

    What Is the Energy of a 3p Electron in Lithium?

    Homework Statement The ground state of lithium (Z=3) has two electrons in the 1s level and one in the 2s. Consider an excited state in which the outermost electron has been raised to the 3p level. Since the 3p wave functions are not very penetrating, you can estimate the energy of this electron...
  8. A

    Mass of an Atom and magnetics problem

    Homework Statement The mass of an atom can be determined by ionizing it and accelerating it through a known electric field followed by a known magnetic field. The ion’s circular path is then measured. Calculate the mass of a chlorine anion of charge 3.20 x 10-19 C if it follows a circular...
  9. D

    Excited hydrogen atom and wavelength

    i have been working on this question for quite a while. no help on google, or my textbook at all. A hydrogen atom in its ground state is excited to the n=5 level. It then makes a transition directly to the n=2 level before returning to the ground state. A) What are the wavelengths of the...
  10. A

    Can an Atom Become a Black Hole?

    good morning everybody i had a question that i found no answer for it on the internet can one atom become a black hole ?? if no, what is the condition that prevent it ?? hope you help me answering this question best regards
  11. X

    A plane wave vs the bound state of Hydrogen atom: orthogonal?

    These days I met one problem and asked a professor for help. But I can not understand his answer. Can you help me explain his answer? My question is that whether we can assume that a plane wave is orthogonal to the bound state of Hydrogen atom when t->\infty? Professor answers...
  12. F

    Hamiltonian for a Hydrogen atom

    The Hamiltonian for a Hydrogen atom in Cartesian Coordinates (is this right?): \hat{H} = - \frac{\bar{h}^2}{2m_p}\nabla ^2_p - \frac{\bar{h}^2}{2m_e}\nabla ^2_e - \frac{e^2}{4\pi\epsilon _0r} In Spherical Coordinates do I just use: x=r sin θ cos φ, y = r sin θ sin φ, and z = r cos θ?
  13. C

    How Long Ago Did the Supernova Occur That Created Earth's Heavy Elements?

    All the very heavy atoms found in the Earth were created long ago by nuclear fusion reactions in a supernova, an exploding star. The debris spewed out by the supernova later coalesced to form the sun and the planets of our solar system. Nuclear physics suggests that the uranium isotopes 235U...
  14. T

    Emission in hydrogen atom - difference between electrons and photons

    A gas composed of hydrogen atoms in the ground state is bombarded with electrons of energy 12.5eV. a) What wavelengths emitted can we expect to observe? b) If we replaced the incident electrons with incident photons of the same energy, what would happen? I know the answers to both...
  15. Q

    Schrodinger equation and hydrogen atom

    Homework Statement Find the width L of a one-dimensional box for which n=5 level would correspond to the absolute value of the n=3 state of a hydrogen atom Homework Equations am i suppose to use n2h2/8mL2 where n=5 to equate it to the n=3 state of the hydrogen atom? which is -13.6eV/32...
  16. Shackleford

    The Bohr Model of the Hydrogen Atom

    A hydrogen atom in an excited state absorbs a photon of wavelength 434 nm. What were the initial and final states of the hydrogen atom? E = hf = Eu - El = 2.825 eV That's the difference in energy between the initial and final states.
  17. A

    Atom Orbitals: Exploring the Electron Cloud Theory

    Atom orbitals, I mean the ones where electrons orbit proton with continuous trajectory like planets orbit around the sun. I do not mean to disagree with modern teachings nor to speculate, I simply do not see how QM actually excludes this possibility. I just want someone walk me through several...
  18. M

    There is no such thing as empty space in an atom. True?

    There is no such thing as empty space in an atom. String Theory Amendum Another question that bothers me. We are taught that the atom is mostly empty space and I understand Bohr's atom and the concept of quantum. No problem. However, there is a movement in physics that states the "empty...
  19. Q

    Positronium atom transition - energy of photon

    Homework Statement Positronium is an atom formed by an electron and a positron. It is similar to the hydrogen atom, with the positron replacing the proton. If a positronium atom makes a transition from the state n = 3 to a state with n = 1, the energy of the photon emitted in this...
  20. S

    Energy of a state of a hydrogenic atom

    Homework Statement One of a He+ atom is in a pure state |1,0,0>. What is the energy of this state? Give a numerical answer in eV. Another of these is found to be in a mixed state: |si>=[1/(3^1/2)][2^1/2|2,1,0>+|2,1,-1>. Calculate the following expectation values at t=0; <E>,<Lz>,<Lx> HINT...
  21. C

    String Theory: Is an Atom Made of 1 or Millions of Quarks?

    in string theory is it that each quark of an atom has one string or is it made up of millions? i know this is a kinda silly question
  22. A

    Hydrogen atom vs hydrogen nucleus.

    Homework Statement A hydrogen atom has a diameter of approximately 1.06x10^-10 m, as defined by the diameter of the spherical electron cloud around the nucleus. The hydrogen nucleus has a diameter of approximately 2.40x10^-15 m. (a) For a scale model, represent the diameter of the hydrogen...
  23. W

    Energy levels of carbon atom electrons

    Homework Statement Consider a neutral carbon atom that has six electrons orbiting the nucleus. Suppose that five of the electrons are in their lowest states,but the sixth is in a very high state. Why might the energy levels for the outermost electron be similar to those for the single...
  24. D

    Energy of electrons in an atom

    Homework Statement An atom confines electrons to be within a certain region of space. Use this fact to estimate the energy of electrons in atoms and compare it to those predicted by Bohr theory, remarking on any differences or similarities. Homework Equations Schrodinger's Wave Equation...
  25. S

    Energy Principle and Hydrogen Atom

    hydrogen atom is formed by the combination of electron and proton initially separated by in finite distance ,therefore, energy of hydrogen atom is expected to be equal to loss of electrostatic potential energy,but according to quantum mechanics it is not so.Is basic energy principle violated?
  26. K

    Probablity density of 1s in hydrogen atom

    I have two asks first ask : In plot of probablity density of 1s electron of hydrogen atom when r=0 where electron exist ? is inside nucleus?! how happen this second ask what is the reduis of electron ri? and what reduis of nucleos RI is ? in Hamltonain operator i mean the...
  27. K

    Graph of potential energy versus internucleon distance in an atom

    The graph of potential energy of a pair of nucleons as a function of their separation shows a minimum potential energy at a value r (approx. = 0.8 femtometers). Below r the PE is positive (actually rises sharply from a negative to a positive value). Above r the PE is negative, and becomes zero...
  28. L

    Changing Oxygen Atoms: Is It Possible to Alter Element Composition?

    As stated in the title. Is it possible? Say for example, if I have an Oxygen Atom. Is there anyway I can add in another proton to this Oxygen atom such that i can change it to some other element?
  29. V

    Solving 1 electron atom Schrodinger Equation in rectangular coordinates?

    Hi, I'm a physics undergraduate, and I'm having trouble understanding Atomic Physics right now. At first I thought it (the question in the title) is possible, but then I think I got confused with particle in a box. So I refer to textbooks and look for answers in the internet, and confirmed...
  30. C

    Comparing Atom Sizes: Be vs B & P vs Cl

    Homework Statement I have a few questions here that say to identify which atom from each pair is larger. One pair is Be and B, and the other is P and Cl. Homework Equations N/A The Attempt at a Solution I know that Be is larger than B, and that P is larger than Cl. I'm just...
  31. S

    Quantum mechanics hydrogen atom

    The hydrogen atom is formed by the combination of proton and electron initially separated by infinite distance therefore energy of hydrogen atom is expected to be equal to loss of electrostatic potential energy but energy value as derived by quantum mechanics is different Why is it so
  32. K

    Energy of electron in the hydrogen atom

    . Homework Statement [/b] In a hydrogen atom the electron and proton are bound at a distance of about 0.53A. (a) Assuming the zero of potential energy at infinite separation of the electron from the proton, what is the minimum work required to free the electron? (b) What would the answer...
  33. Q

    Ground state energy of a two particle gravitational atom

    Homework Statement Two neutral spinless particles of mass m are gravitationally bound to one another. What is the ground state energy of this two-particle gravitational atom? Homework Equations The Attempt at a Solution So, it's a two particle system, but H_{total} = H_1 +...
  34. S

    Charge densities within an atom

    Homework Statement A hydrogen atom might be modeled as a sphere of charge +e and radius 10-15 (the nucleus), surrounded by a sphere of charge −e and radius 10-12m (the electron cloud). (a) What is the average charge density of the nucleus? (b) What is the average charge density of the electron...
  35. H

    Hydrogen Atom; energy state transitions

    Homework Statement A hydrogen atom is initially in the state n=3. Subsequently it falls to its ground state with the emission of a photon. If the photon energy is ћω , then what is the ground state energy? The Attempt at a Solution I tried using E= h².n²/8ma². and got -9ћω/8 I wasn't to...
  36. T

    Does an Atom Lose Energy? Understanding the Role of EM Waves and Photons

    Hi I was wondering whether atom loses its energy. From what I know, a moving charged particle, let`s say electron, has magnetic field and if the particle changes direction, the field changes as well. Change in electro-magnetic field is a wave, EM waves are propagating in photons and a photon...
  37. Q

    Potential energy in hydrogen atom

    Can somebody elabroate on how the P.E. term e^2/r is thrown in shrodinger's(also Dirac) equation for the hydrogen atom by assuming such term does describe the effects of the negative and the positive charge. It enters into the equation like mass, yet quantum theory( a good one) should calculate...
  38. K

    Algebraic solution of hydrogenic atom

    I've read that the hydrogen atom was solved by means of algebraic methods (similar to creation and annihilation operator for the harmonic oscillator) even before the works of Heisenberg and Schroedinger. Could you give me some information and/or references about this issue?. Thanks, Kowalski.
  39. D

    Understanding Electron Probability in Atom

    I know that electrons do not exist in orbitals, but instead in probability density clouds around the atom. I know that these electrons are quantized and can only have certain energies in the atom. I also know that it is due to the Heisenberg Uncertainty principle that these atoms do not crash...
  40. J

    Classical Physics and the Bohr Model of Hydrogen Atom

    Homework Statement Classical physics applied to the bohr model of the hydrogen atom would predict that light could be emitted continuously, rather than in discrete chunks of energy. Transitions between what kinds of energy levels would come close to the classical viewpoint? A. Only levels...
  41. P

    Formula for expectation value of raidous in Hydrogen atom

    Let's consider eigenstates |nlm\rangle of hamiltonian of hydrogen atom. Can anyone prove that \langle r \rangle = \langle nlm|r|nlm\rangle = \frac{a}{2}(3 n^2-l(l+1)). Where a - bohr radious. I've been trying to prove it using some property of Laguerre polynomials (which are radial part...
  42. deccard

    Emission in hydrogen atom: recoil and photon properties

    I have been trying to picture the whole process of a photon emission by a atom. So to have good understanding what is going on, I have came up with following experimental setup. A single hydrogen atom in excited state ^2\!P_{1/2}, which has been orientated with a magnetic field so that...
  43. L

    Modelling the shape of an atom

    hi, when modelling the shape of a hydrogen atom orbital, is it the real part of the spherical harmonics that i plot? thanks
  44. D

    Excited vs. Ground state masses of atom

    1. In a certain gamma decay process, an excited neon atom emits a gamma-ray that has an energy of 1.630 MeV. The neon atom in the ground state has a mass of 19.992 435 u. What is the mass of the excited neon atom? 2. I am pretty lost here. There must be a formula relating these...
  45. D

    Finding Absorption Lines in Hydrogen Atom (n=10)

    Could anyone help solve a problem how to find absorption lines in hydrogen atom from n=10 (n - principal quantum number). I know that not all quantum jumps of an electron in atom are possible, thus I don't know how many different emission lins will be from this energy level where n=10.
  46. M

    Hydrogen Atom Radial Wave Function (limit problem)

    The Hydrogen Atom wave function. With the substitution u(r) = r.R(r) p=kr We get a simplified version: d^2u/dp^2 = [1 - (p_0)/p + l(l + 1)/(p^2) ].u Im sure some of you have seen that before. Now, in the limit, p goes to infinity, I understand that we get u = A.exp[-p], but in...
  47. Spinnor

    How little does a hydrogen atom curve space?

    I assume general relativity allows us in principle to calculate volumes of some region of space? If so, if I have a large volume of space far from other mass and energy does it make sense to ask how much a large volume of space changes depending on whether or not it contains the mass of single...
  48. J

    Calculating Electric Force in Bohr Model of Hydrogen Atom

    Homework Statement In the Bohr model of a hydrogen atom, what is the magnitude of the electric force exerted between the proton and the electron when the electron is in the n = 1 state? Homework Equations E= - 13.6 eV/ n^2 The Attempt at a Solution I simply...
  49. M

    Lorentz Cavity in Uniformly Polarised Dielectric: Exam Question

    I just have a small question regarding lorentz cavity: Refer to a small lorentz cavity in a uniformly polarised dielectric. as shown in fig. E_{ex}: External electric field. E_{P}: Electric field in the uniformly polarised dielectric (when sphere has NOT been cut out) E_{L}:Electric field...
  50. C

    Calculating Spring Constant using Minimum Energy State of hydrogen atom

    Homework Statement A hydrogen chloride molecule may be modeled as a hydrogen atom (mass: 1.67 x10^-27 kg ) on a spring; the other end of the spring is attached to a rigid wall (the massive chlorine atom). If the minimum photon energy that will promote this molecule to its first excited...
Back
Top