Atomic Definition and 812 Threads

  1. M

    Help needed badly in understanding the concept of atomic masses

    i hope everyone's in fine health in this fine thursday evening. :approve: ok i just had some general questions on atomic masses, and to the chemists in here, i appologize if these questions are a bit too basic for you. :cry: but ur help and time is greatly appreciated nonetheless! :smile...
  2. H

    How Do Atomic Clocks Differ from Orbital Clocks in Measuring Time?

    I must be confused about the differences between atomic clocks and orbital clocks. Here is what I read on one site. http://www.ldolphin.org/setterfield/redshift.html The faster the velocity of light, the faster an atomic clock beats. I can undertand that. Dynamic clocks run independently, but...
  3. A

    Why Do Electrons Prefer Half-Filled and Fully-Filled 3d Sublevels?

    i still don't understand why when the 3d sublevel is half-filled or completely filled we get : 3d5 4s1 or 3d10 4s1.. I need a real expert to clarify it for me.. Please its urgent. Thanks Joe
  4. recon

    Calculate the average Relative Atomic Mass of this sample of krypton

    When an evacuated glass bulb of 1.00 dm3 capacity was filled with a sample of krypton at a pressure of 1.00 X 105 Pa and at a temperature of 300K, its mass increased by 3.32 g. Calculate the average Relative Atomic Mass of this sample of krypton. It's the 'mass increased by 3.32g' part that...
  5. R

    Atomic Spin: Origin in Nucleus & Impact of Electrons

    Is the spin of an atom come from (or based on) the Nucleus (i.e. net of Neutrons and Protons)? With the spin of the Electrons not really noticed or counted though a sense of being ‘lost’ or masked by being in an orbital?
  6. N

    Atomic theory in another planet - problem

    In a planet, if the spin numbers were +1/2, 0 , and -1/2 and their magnetic quantum numbers take the values 0, 1, 2,...L ( Everything else including the ordering and naming of the orbits are same except the spin numbers and the magnetic quantum numbers as provided above.) how would the...
  7. D

    Linear Combination of Atomic Orbitals

    Is anybody familiar with LCAO approximation? I'm working on my last problem for this assignment and the class text doesn't really cover it enough for me nor do my reference texts cover it enough. Does anybody know any good references so I can read more on LCAO approximation? Thanks.
  8. J

    How Do You Determine Quantum Numbers from Hydrogen Spectra Data?

    I did a spectroscope experiment with a hydrogen discharge tube. So far I got this data: Line 1: Color=Red \lambda(nm)=700 \nu(Hz)=4.2*10^{14} n1=? n2=? \Delta{E}(J)=2.8*10^{-19} E(J)=? This is only the data for the Red line. I figured if i knew how to do this, I'll...
  9. B

    How can atomic spectra be only certin frequencies?

    I don't know a whole lot about quantum mechanics and there is something that dosen't make sense to me. An atom absorbes radiation in only certin frequencies. Do these frequencies have to be exact? Can they vary over a small range like say 1.000 to 1.001 or do they have to be perfectly exact...
  10. V

    Atomic & Nucleonic Radius of Iron | Vince

    Does anybody here know where to find the atomic radius of elements in the periodic table? What about the nucleonic radius? I'm currently trying to find the radius of Iron for some sort of calculation that I'm doing. Thanks -Vince
  11. R

    Impact of concepts on Atomic Theory

    During most of the 19th Century physicists believed that atoms were the smallest particles of matter and thus couldn’t be further subdivided. With such characteristics, an atom of one element obviously couldn’t become an atom of another element – a process they labeled “alchemy”. J. J...
  12. N

    Do Transition Elements Follow Main Group Trends in Atomic Radius?

    im just doing a lab right now on atomic radius' and there's one question that asks, Would the transition elements follow the same trend that the maingroup elements follow for their atomic radius'? i guessing yes, but I am not too confident with my answer. anyone have any idea or know of...
  13. T

    Atomic Structure: "Long Range" and "Short Range" Translation

    Hi everyone I missed some content in my lecture about atomic structure of atoms. In the lecture, the lecturer talked something about "slipping" , "easy directions" and "slip systems"...I don't really catch these stuff in this lecture. But I could find these in textbook. What makes me most...
  14. O

    What Are the Key Differences Between Bohr's Atomic Model and Classical Physics?

    I need help with these 3 questions: 1. Describe the Bohr model of the atom. How does it differ from a planetary model based on classical physics? ======================== 2. In terms of the Bohr theory why is that electrons don't spiral into the nucleus? ======================== 3. If...
  15. P

    Atomic Derivation of the characteristic impedance of the vacuum

    Can anyone here use Bohr's analysis of the hydrogen atom, to compute the characteristic impedance of the vacuum? And if not, then how would the Bohr model need to be modified, in order to obtain Z0? Characteristic impedance of the vacuum = Z_0 = 376.730 313 461 ohms CODATA value...
  16. U

    Monuments of atomic structures

    i was given this task - find at least 2 cities which have a monument of atomic structure and give the name of the element of which the structure is. :confused: for example, there's an atomic structure of iron in Brussels named Atomium http://www.trabel.com/brussel/Brussel-HeyselAtomium.htm...
  17. D

    Determination of the atomic radius of an Al atom

    hi everyone, im trying to find the atomic radius of an Al atom using a few measurements i have. i had a piece of aluminum foil its measurements were [ 10cm*9.9cm*0.0014cm ]. The mass of the aluminum foil was 0.40 grams. Is there any possible way i can find the radius of an Al atom? I know i...
  18. J

    Question: localised mode, localisation effect of linear atomic chain

    urgent question: localised mode, localisation effect of linear atomic chain Hello everyone, it is great place you have here, hope I can learn a lot from you I am doing some readings and there are couple of concepts that I haven't been familiar with and if you spend a little time to help me...
  19. A

    News Does anybody know which are the comp-onents of the atomic bomb

    Does anybody know which are the comp-onents of the "atomic bomb" Thank-you for your help...
  20. B

    Atomic and Nuclear Radii Evidence: An Overview of Size Scales in Atomic Physics

    Describe briefly one piece of evidence for each of the following statements. i) Atomic radii are about 10^-10m ii) Nuclear radii are about 10^-14m Each part is worth 4 marks, so I would really appreciate if someone could reply with some slightly easy to understand, but quite detailed...
  21. P

    Atomic Structure: Explaining n=6 Shell & Largest Angular Momentum Quantum Number

    [FONT=Comic Sans MS]I need a plain & simple explanation of atomic structure. For example, if I was to consider the n = 6 shell, what would be the largest angular momentum quantum number and how many electrons can be put in this shell? Thanks for your insight!
  22. R

    Could someone explain fire on the atomic level?

    could someone explain fire on the atomic level? in six easy pieces it says heat is usually in the form of molecular motion but sometimes it can be so enormous that it generates light. but how? can the motion of these molecules form other types of electromagnetic radiation (secondary question)?
  23. P

    In Desperate Need of Help (Dalton's Atomic Theory)

    Okay, here's the problem: For my freshman chem class we need to know which of Dalton's 4 atomic theories were disproven. There are two of them. I can't figure out which ones. Also, we need to know why they are wrong. I need this by tonight. Someone please help me! :bugeye: Thank you...
  24. D

    Gravity and atomic fields - due to high relative motion?

    Gravity or gravitational fields are not yet understood fully. All mass bodies including the atom itself has what is called a gravitational field. Gravity is principly the partial alignment of the atomic electrical fields due to a common high velocity motion of the atoms through the universe...
  25. ?

    Atomic radius - core charge vs energy level

    which one is more important in determining the size of an atom? for example - Berilium has a smaller radius than Lithium because it has a greater core charge, but what about Nitrogen vs Berilium? Nitrogen has a greater core charge, but it has electrons in the 2p subshell whereas Berilium only...
  26. Z

    Atomic simulation and lots of questions

    First, hi. This is my first post, and after careful perusing of the forum I *think* this post is in the correct place. Feel free to move it around if not, apologies. The meat of my questions. I'm a High School student that would like to simulate atoms on the computer. I've been getting...
  27. F

    Atomic Packing Factor of Simple Hexagonal Unit Cell

    How would I go about finding the APF for a simple hexagonal unit cell. Which is a rectangle. I know one length is a0(HCP) but I cannot figure out the other side of the rectangle. Also, wouldn't the height be the c?
  28. F

    Relative atomic mass of an element ?

    relative atomic mass of an element ? A sample of neon was found to cotain 90.9% of 20Ne, 0.26% of 21Ne, & 8.8% of 22Ne, Calculate the relative atomic mass of neon. this is what i'v done so far (90.9x 20)+ (0.26x21)+(8.8x22)= 2017/? i don't know what to divide it by :confused: ? I'm not...
  29. S

    Build a microscope that sees at the atomic level?

    I am curious about microscopes, I know i could buy an optical one for around $200 $500, i am wondering about how hard it would be to build a microscope that sees at the atomic level? I imagine buing one is pricey. Is it within the budget and access of Average Joe to build a microscope that powerful?
  30. M

    Quantum Tunneling and atomic spectra.

    Can somebody explain quantum tunneling to me? And the thing about why amplitudes when they are trapped, the energies must choose from a distinct set of values? And why when particles that are totally free to wander will have any energy that they like? Also, why in the atomic spectra, more...
  31. E

    Formula for calculating the atomic or covalent radii of elements

    Is there a formula for calculating the atomic or covalent radii of elements, isotopes or ions?
  32. Y

    Quantum physics & Atomic Physics Question

    Hi, I've been trying to figure these two questions out but they haven't beeen working. 1. A hydrogen atom is in its fifth excited state. The atom emits a 1090 nm wavelength photon. Determine the maximum possible orbital angular momentum of the electron after emission. Express your answer as...
  33. B

    Did the Apollo Missions Use an Atomic Clock for Time Dilation Experiments?

    Did they take an atomic clock on one of the Apollo missions for time dilation experiment if not why not ?
  34. C

    Where is the Evidence for Atomic Structure Theory?

    i am a person who just asks where the proof is about everything...so where is the proof of the Atomic Structure Theory? have we even seen an atom? have we seen a proton, electron, neutron, anything like that? don't even think of using the bubble chart/graph as an attmpt to prove anyhting with...
  35. T

    Enriching Uranium: Gas Centrifuge Method

    Homework--- Build Atomic Bomb What is the general output of enriched uranium from an electrolysis and fractional distillation process? I have already researched the outputs for gas diffusion, thermal diffusion, gas cenrifuge, laster isotope separation, and mass spectroscopy. If you could give...
  36. T

    Atomic Question-- Enriched Uranium Output From Processes

    Atomic Question-- bomb What is the general output of enriched uranium from an electrolysis and fractional distillation process? I have already researched the outputs for gas diffusion, thermal diffusion, gas cenrifuge, laster isotope separation, and mass spectroscopy. If you could give me any...
  37. I

    Atomic Physics: Finding Energy Levels

    i am having problems with the atom model part of physics, i know that the current model stats the electron location is a probability and all, its when i get to the wavelength and the energy, with all the ionization and the spectrums that i don't understand... how can i find the energy level...
  38. K

    Why Multiply Carbon Isotope Mass Numbers by 1.67x10^-27 kg?

    Here's a verbatim section of the problem: " The source contains carbon isotopes of mass numbers 12, 13, 14 from a long-dead piece of a tree. (To estimate atomic masses, multiply by 1.67x10^-27kg). " My question is isn't the 12, 13, & 14 in the atomic mass units already (Carbon-12 has an amu...
  39. W

    Arraging atoms/ions based on atomic radius

    Arranging atoms/ions based on atomic radius Hey, I'm in a bit of a bind here. I got a question that deals with atomic radius. The question asks to arrange the following atoms/ions in order from smallest to biggest: Cl, S^{2-}, K, K^{+}, O I know just by looking at the periodic table that...
  40. E

    How Does Atomic Theory Explain the Increase in Resistance with Temperature?

    I have a problem in my book, "Using the atomic theory of matter, explain why the resistance of a material should increase as its temperature increases". I can't think of one way that the two relate, but that could be because I don't fully understand what resistance is (on a molecular level)...
  41. C

    Simple Measurement of Atomic Nuclei Radii

    Okay, we have a graph that shows how v.high energy electrons are diffracted by atomic nuclei and the first minimum is shown to be at approximately 51 degrees for carbon-12 with energy 420MeV. To calculate the nuclear radii I decided to use sin(theta)= 1.22lambda/d and rearranged this so d was...
  42. R

    The Atomic Mass - Calculating the Weight of Gallium Atoms

    The Atomic Mass! Hello, I have a problem of getting the answer of this question and I still don't understand it. The question is What I though is that the answer is "1,700,000,000,000,000,000" and I thought it's same as when we say we have a red apple and how many red apples are in...
  43. B

    How Maxwell's theory of radiation could not explain atomic spectra?

    We all know that Maxwell did such a great work for all physicist. BUT, anyone knows that how Maxwell's theory of radiation could not explain atomic spectra?
  44. M

    Dating methods: calculating atomic ratio?

    Please help me with this calculation. I read that chapter in my book three times now and still don't know what actually do to calculate the atomic Rb-87/Sr-86 ratio of a rock sample containing Rb=125 microg/g and Sr=275 microg/g. Atomic weights: Rb=85.46, Sr=87.62 isotopic abundancy...
  45. M

    God's Spectacular Atomic Engineering

    With your prodigious font of scientific knowledge, you are assigned the project of designing a series of unique materials from only three separate building blocks. Your constraints are as follow: 1. Make 92 different materials differing wildly in their physical and chemical properties...
  46. A

    Calculating Atomic Bomb Shockwave and Blast Radius Formula

    Hi everyone. I've been searching google for a clear formula and formulas for atomic/nuclear bomb shockwave and blast radius. I haven't come across anything remotely close that details the effects of time on the effects of the bomb as it crosses a set distance. Can some one help me with the...
  47. S

    Why is there a difference in atomic and ionic radii for Ca and Zn?

    hey guys! I was just wondering if anyone could help me out a bit on this. I have the following radii (in angstroms...not that it really matters) Ca: 1.74 Ca 2+: .99 Zn: 1.31 Zn 2+: .74 Does anyone have any idea why the difference between the atomic radii of the two elements is...
  48. Q

    What is the truth behind the atomic model?

    Please, take a look on my atomic-model based on that a universe in which every point can be counted as an origo, must be a net. https://www.physicsforums.com/showthread.php?s=&threadid=8610 You can also read the rest of my theory on http://www.quantumnet-string.tk This explains the...
  49. M

    Is the atomic structure correct

    ive recently been reading about the string theory and of course learned that it is attempting to unify the forces. for a while now i have had an idea that its unlikely that matter could actually have multiple quantum forces and by eliminating two potentially unnessecary forces (weak and...
  50. P

    Gravity at atomic levels, first time post

    I have very little training in the area of Physics, but enough to understand most of what is said on this forum. This is a first time post. My question has to do with gravity on an atomic level. This question is for those of you familiar with trying to combine all four natural forces...
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