Atom Definition and 999 Threads

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).

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  1. H

    What is the Ionization Energy of Lithium?

    Homework Statement Estimate the ionization energy of Lithium. Neglect the repulsion between the electrons. Homework Equations what is the equation that can be used here? There are thousands of tables in the web having tabulated the values of various ionaziation energies. But one can hardly...
  2. S

    Two hydrogen atom with same spin can form H_2?

    As I know from the laws of chemistry,to form H_2 the H atoms must have opposite spin. What if they have the same spin? I mean, can an H atom rotate to swap his spin (i'm not expert of the dynamics of spin), or there is no way to couple them? In the case I have a gas of H with all of them...
  3. fluidistic

    Electrons and their quantum numbers for the oxygen atom

    Homework Statement Write down the electonic configuration for the O atom. Write down the quantum numbers (n,l,m_l,m_s) for each one of the electrons. Homework Equations Pauli exclusion principle. Least energy principle for filling the shells. The Attempt at a Solution...
  4. M

    Fine structure correction in H atom

    Hi, I refer to the second edition (international edition) of Griffiths. He proves that the total fine structure correction (spin orbital plus relativistic) is given by E_{fs}^{1}\propto (3-\frac{4n}{j+1/2}) After that, he writes this. "Fine structure breaks the degeneracy in l (that is, for a...
  5. M

    Total magnetization of an isolated atom

    im trying to study an isolated atom(Boron) and i can't for the life of me figure out what to do with the total magnetisation, which is defined as : further more: what are these guys talking about? is this explained out in detail somewhere in ENGLISH for humans? cheers mechdude
  6. A

    Help Solve a Puzzling Two-Level Atom Problem

    Hi, everyone! I would really appreciate your help with this one! I've been looking at a simple problem, linearly polarized excitation scheme in a two-level atom, J_g=J_e=1. At first orientation of coordinate system is such that light is polarized along y direction and propogates in z...
  7. L

    Wave function of a two atom system

    Homework Statement what is the possible wave functions of a two hydrogen atom system under a pertubation, if one of them was perpared in 2s0 and the other was perpared in 2p0 state.Homework Equations The Attempt at a Solution I have no idea of the total wave function should be the sum of both...
  8. fluidistic

    Fine structure, hydrogen atom, principal quantum number 3

    Homework Statement The level n=3 for atoms with 1 electron have the states 3s_{1/2}, 3p_{1/2}, 3p_{3/2}, 3d_{3/2}, 3d_{5/2}. If we ignore the spin-orbit coupling these states are degenerated. Calculate the degeneration due to the the spin-orbit coupling for the levels 3p and 3d for the...
  9. R

    Orbital Frequency of an electron in a hydrogen atom

    Homework Statement In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. What is the electron's orbital frequency? What is the effective current of the electron? Homework Equations Freq * Wavelength = Speed of...
  10. E

    Energy needed to split an atom

    Is there a table or a graph out there that states the amount of energy needed to split an atom? I know about ionization energies and all that, but there wasn't anything on the internet on how much energy is required to ionize the whole atom. Thank you in advance
  11. S

    Use Uncertainty Principle to estimate the size of the H atom

    Homework Statement In Bohr model of the hydrogen atom, the max. kinetic energy that an electron can have is around 13.6 eV, as it would otherwise not be confined to the atom. Uncertainty Principle: ΔxΔy ≥ h/2π a) Find the max. momentum of such confined electron. b) Use Uncertainty Principle...
  12. A

    How do you find the charge of an atom?

    Calculate the electrostatic force between a proton and a gold nucleus Au with a distance 7.5x10-13m 19797Au The Electrostatic force is (Q1Q2)/4∏ε0d2 Two things I want to know, the charge of the gold and how to find the charge of Atoms! All I need to know is the charge, I can do the rest!
  13. A

    Quantum Mechanics and the Hydrogen Atom

    Calculate the expectation value of the potential energy for an electron in a 1s orbital for a hydrogen atom Ive determined the potential energy operator to be V=-e2/4∏ε0r and a wave function of ψ= (1/4∏)1/2 therefore i get <V> = ∫∫∫ψ*Vψr2sin∅drd∅dphi integrals from 0 to r...
  14. D

    Subatomically, what causes an atom speed up when it has a chemical bond broken?

    Homework Statement According to the molecular biology book I am reading, when a chemical bond breaks, the energy in the bond is released in the form of heat. which is to say, when a chemical bond breaks the entire atom's speed increases (the atom gains 'heat energy'). But what is...
  15. S

    How do electrons become excited in an atom

    I was wondering why hot objects glow (such as a heated metal), what I found on wiki: "Thermal radiation is energy emitted by matter as electromagnetic waves due to the pool of thermal energy that all matter possesses that has a temperature above absolute zero. Thermal radiation propagates...
  16. J

    Definition of an unstable atom.

    Homework Statement Definition of an unstable atom Homework Equations The definition = the answer. The Attempt at a Solution My guess is an atom with an unbalance in the strong or weak nuclear forces, leading to radioactive decay. Does anyone have any better ideas?
  17. A

    Translational movement of a signal atom in a vaccuum?

    I had a thought-experiment I was pondering the other day. If you could somehow isolate a single atom inside a vacuum inside a Faraday cage, how would that atom behave in terms of translational movement?
  18. fluidistic

    Second order DE (hydrogen atom)

    Homework Statement The DE y''+\frac{2}{x}y'+ \left [ K+\frac{2}{x} - \frac{l(l+1)}{x^2} \right ]y=0, 0<x< + \infty. appears when working on the hydrogen atom. Find all the values of K (the eigenvalues) that generates solutions of the form \phi (x) such that \phi (x) remains finite when x...
  19. T

    Infinite number of energy levels available to an atom

    I'm confused about something. If there are an infinite number of energy levels available to an atom, how and why would an ionization need to take place? The electron always has another energy level to occupy once its energy has been raised.
  20. P

    Dirac Equation for H atom - what's the small r behaviour?

    The Schrodinger wavefunction for the hydrogen atom scales as r^l for small r, where l is the orbital angular momentum. Is this changed in any dramatic way for the Dirac equation wavefuction? Does the small component of the Dirac spinor have the same small-r asymptotic behaviour as the large...
  21. O

    H atom electron in combined spin/position state

    Homework Statement An electron in a H atom occupies the combined spin and position state: R21{(sqrt(1/3)Y10χ+) + (sqrt(2/3)Y11χ-)} If you measured both the z component of spin and the distance from the origin, what is the probability density for finding the particle with spin up and at...
  22. K

    Energy level of hydrogen atom - with the electron replaced by a positron

    Energy level of hydrogen atom -- with the electron replaced by a positron The energy level of a hydrogen atom is given by (without fine structure consideration) Eh = -13.6 eV / n^2 Suppose -- if the electron is replaced by a positron, what would happen to this energy level? The resulting...
  23. L

    Electrical stability of an atom

    Homework Statement As shown in class the electric potential energy of a water molecule is -5.33 eV. Which molecule is more electrically stable, H2O or CO? Why? Homework Equations EPE=Kc*q1*q2/r12 The Attempt at a Solution The water molecule's EPE is -5.33 eV. The carbon...
  24. B

    Normalise wavefunction of hydrogen atom

    Homework Statement An electron in a hydrogen atom is described by the wavefunction: psi(r) is proportional to (psi(subscript 100)+2psi(subscript 210)-3psi(subscript 32 -1) -4psi(subscript411)) where psi(nlm(subscript l)) are the eigenfunctions of the hydrogen atom with n, l...
  25. D

    Quantum Model of an Atom with more than one electron

    Hi, I just completed an assignment modelling an atom with one electron. The model was very simple, assuming that only coulombs law applied, then solving for standing wave solutions to the Schrodinger equation to find ionization energies. I was astounded how accurate it was. i thought it would...
  26. D

    [Nucl Physics]alpha particle and beryllium atom collison

    Homework Statement what is produced when an alpha particle reacts with a beryllium atom Homework Equations The Attempt at a Solution i think that carbon 12 and a neutron is produced. please help me.
  27. H

    Magnitude of Electric Field from an Atom

    Homework Statement The neutral neptunium atom has 93 electrons. What is the magnitude of its electric field at a distance of 6.5x10-10 m from the nucleus? Hint: The number of protons in a nucleus is equal to the number of electrons in the neutral atom. q = 1.6e-19 * 93 = 1.48e-17...
  28. J

    What is the origin of a neutrino? from which part of the atom it

    what is the origin of a neutrino? from which part of the atom it comes?
  29. H

    What's wrong with my Q550 atom CPU?

    What's wrong with my Q550 atom CPU?? I brought a Fujitsu Q550 one week ago from J&R via Amazon. I would like to use it with Onenote for jotting note during class However, it is running very slow, I would barely use the Onenote alone, can't open any other pdf ebook at the same time, otherwise...
  30. H

    Can Atoms Be Made of Different Fermions?

    hi, i have been reading this book about antimatter, "Antimatter" by Frank Close, and have a question. CAN ATOMS BE COMPRISED OF DIFFERENT FERMIONS OTHER THAN PROTONS, NEUTRONS, AND ELECTRONS? could they be comprised of those fermions if they have the same charges as protons, neutrons, and...
  31. S

    Protons/Neutrons/Electrons in Function to the Atom

    Homework Statement How many electrons, protons, and neutrons are there in an atom of 162Dy? If the gravitational force suddenly vanished, what would happen within the atom? If the electromagnetic force vanished what would happen? What would happen if the strong nuclear force disappeared...
  32. M

    Atom Interaction: Solving T=E^2/4*(M+m)c^2

    Homework Statement The problem is attached Homework Equations T=E^2/4*(M+m)c^2 M=61amu, m=1amu E=710kev c=3*10^8m/s I conver amu to kg The Attempt at a Solution direct subtitution but the thing that I got the answer which is 2.21eV which is very small and it confused me have I...
  33. chaszz

    Charge attraction inside an atom

    If the electrons in an atom are negatively charged, and the nucleus is positively charged, what keeps them from coming together? I know that the old model of an atom as a tiny solar system is long obsolete, but still, there is supposed to be some discrete space between the electron structure...
  34. K

    Why does the atom not fold onto itsef?

    If the atom is composed of a nucleus with positively charged subatomic particles, and the electrons are in the outer orbitals which are defined as in an electron cloud, why doe they not attract and the atom does not collapse on itself due to electrostatic forces of attraction. Also is there a...
  35. fluidistic

    Calculating the Radius & Energy of Bohr's Hydrogen Atom

    Homework Statement 1)Determine the radius of the allowed orbits. Calculate the first orbit of Bohr's model for the hydrogen atom. 2)Show that the energy is quantized. Calculate the energy of an electron on the first orbit (fundamental state of hydrogen atom)Homework Equations L=n \hbar...
  36. A

    How emissions for a spectra provide evidence for energy levels in a atom?

    Explain how data from emissions spectra provide evidence for discreet energy levels within the atom?
  37. S

    How to Calculate Relative Atomic Mass Without Abundance Information?

    Homework Statement 46-Ti 47-Ti Using the information in Table 1.1, calulate the relative atomic mass of this sample of titanium, Give your answer to 3 significant figures. Homework Equations The Attempt at a Solution I only know how to figure out the relative atom mass if...
  38. J

    Radial Probability Distribution Curve for Hydrogen Atom

    I'm trying to plot the radial probability function for a hydrogen atom. I have the function itself (Psi2*4*pi*r2) my problem is that when I plot the function with angstroms on the x-axis, the y-values are larger than they should be (they look about right if I divide them by the bohr radius in...
  39. D

    What incident energy is required to ionize a helium atom?

    Homework Statement The energy required to ionize a helium atom is 24.6 eV. If helium gas is bombarded with charged particles, at what incident energy will ionization of helium just be observed if the projectiles are (a) alpha particles (b) protons (c) electrons? Homework Equations Most...
  40. C

    Can an atom be anywhere in space?

    Is space like a checker board where the pieces can only be in certain places like X X X X X X X X XoX...
  41. M

    Calculating charge density of an atom

    here I am only considering the charge density of the nucleus, i.e the density of protons. I know that from mass density i have rho = m/v -> v = m / rho I'm not sure what mass to use here. Molecular weight? molar mass? where does avagadros number come into it? then is it simply charge...
  42. D

    How to prove there is no primitive cell of diamond structure with only one atom?

    How to prove there is no primitive cell of diamond structure with only one atom? Thanks in advance!
  43. M

    Energy of an atom in an excited state

    Homework Statement An atom which is in an excited state, can emit a photon with the wavelength of 330 nm at during the movement between two "energy niveaus". The last niveau has the energy -4.8 \cdot 10^{-19}J. What is the energy of the atom in the excited state? Homework Equations Not...
  44. I

    Can an electron collide with the nucleus of an atom?

    Can an electron (from outside the atom) collide with the nucleus of an atom, and does this happen at normal energy levels? What usually happens when it does? If it doesn't happen is it because the electrons of the atom repel the incoming electron with their charge. Finally same question, but...
  45. L

    Elementary particles -their place in atom

    elementary particles --their place in atom Homework Statement Do elementary particles reside inside the nucleus alone? Homework Equations The Attempt at a Solution
  46. L

    Interpetation of wavefunction - atom

    It's now years since I studied this, if anyone could help me remember. If I look at a hydrogen atom and it's shells. In the ground state there's 1s, the wave function is then: \Psi_{nlm}(r,\theta,\phi) = Y_{lm}(\theta,\phi)R_{nl}(r) = Y_{00}R_{10} Y_{00} = \frac{1}{\sqrt{4\pi}} R_{10}...
  47. O

    Acceleration of electron in hydrogen atom

    Hello, I am currently reading about electromagnetic fields: In one of the examples in the textbook we calculate the electric field of a hydrogen proton. We then compute the electric force acting on the orbiting electron to be 8.2 \times 10^{-8} N So I thought I could get the...
  48. N

    What will happen to trade when atoms can be rearranged at will?

    wen atoms can be re arranged at will, what wil the effect be on trade? wen u can make anything out of anything ths is a serious question, i think Newton was ridiculed an deleted off forums too. very rude! i cud be a genious!
  49. antibrane

    Hydrogen Atom in Magnetic Field

    I am attempting to find the probability, after time t, of a hydrogen atom in a magnetic field \vec{\mathbf{B}}=B_0\hat{\mathbf{z}} to go from \left|n,l,s,j,m_j\right\rangle \longrightarrow \left|n',l',s,j',m_j'\right\rangle where j=l+\frac{1}{2} and j'=l'+\frac{1}{2} or...
  50. D

    Can anyone explain energy levels of an Atom?

    Now, from what I understand, Bohr's model of the atom is outdated and flawed. But whenever I imagine energy levels, it is the Bohr's model that comes to mind. Do electrons really orbit around the nucleus? I would assume because of classical physics, even though the electron can be on any portion...
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