Atomic Definition and 812 Threads

hi guys i was wondering how the coordination numbers for the atomic positions of atoms in crystals such as NaCl are derived ...more specifically why is Na at (0,0,0) and Cl at (1/2,1/2,1/2) and not (0,0,0) and (1/4,1/4,1/4) of course this is in fractional coordinates

What is a good intro to atomic physics book that gives a good physical picture of what's going on.

Hi, Explain in terms of the number of nucleons and the forces between them, why argon-36 is stable and argon-39 is radioactive. My first doubt regards the number of nucleons. If a nucleon is the collective number of neutrons and protons, if we take carbon 12 for example, does it have 6 or...

Homework Statement Given: 5x10^21 Phosphorous atoms/m^3 in solid solution in silicon Find: atomic percent and weight percent of Phosphorous atoms The Attempt at a Solution I know how to solve for at. % and wt. % when given two values, I am not sure how to get the second value given the...

If it is electrical, why is there attraction between atoms? Shouldn't they repel each other due to outer electrons?

Let say we would like to perform such experiment: Let we have 2 small/mobile atomic clocks on a hard rod. (AC1)==============================================(AC2) Distance between clocks about 2 meters. There is no any electrical wire connections between these two clocks for...

I have always been told that scientists such as Mendeleev used atomic mass to list the known elements of their time. I have always been curious as to how those early scientists actually determined the atomic masses of those known elements. What kind of experiment or process/principle was used...

I have a confusing question mainly due to my lack of understanding of Quantum Mechanics and spin! here it goes anyway... In an atomic orbital, like the 1s orbital, two electron waves with opposite spins occupy the same area of space. Now, does this mean that their waves should interfere with...

http://physicsworld.com/cws/article/news/31068 I thought only elctrons could be entangled but now atoms and even ions can be entangled. Would this suggest that it could work its way to the macro levels. Could two diffrent rocks or soccer balls become entangled?

I got a question : Why is the nucleon of Chlorine 35.5 ? Why is is not a whole number ?

Hello, This question is a theory question: I have calculated the moles of molecular iodine in a problem (I2) and the next question asks to calculate the moles of atomic iodine. Do I just multiply the number I have by two (as iodine is a diatomic molecule) or is it a "trick" question and the...

When 2 atoms bond, do all their atomic orbitals combine, or is it just the bonding orbitals that combine? For example when sodium and chlorine bond, do all their orbitals combine or is it just sodiums 3s orbital that combines with chlorines 3p orbital?

Homework Statement The relative population of two atomic population states in equilibrium is given by Boltzmann Distribution: n1/n0 (proportional to) e^(-ε/(κT)) , where ε is the energy difference between the two states, T is the temperature and κ is the Boltzmann constant = (1.38 x...

hi, this is my first forum post, i hope it is in the correct category. i was reading an article last month ... http://www.sciencedaily.com/releases/2011/09/110901142058.htm now at these small distances that can be measured is the hindenburg principle of uncertainty being encroached upon...

Uh, I don't know if this suits the topic, but I've been wondering about this. Are we more times bigger than the smallest particle we know about than we are smaller than the large stars?

So I usually use VESTA to make my figures, and though the new version is able to do many mad things with calculated electron density isostructures and whatnot, I can't seem to just be able to throw in some clover-leaf d or p orbitals like what was done in the image below (from this paper on...

Does anyone have information on how exactly a atomic clock works? I have had advanced quantum mechanics courses so I am sure I wil understand it. My problem is that I can't find any descriptive materials (with drawings), the wikipedia page is very vague about the different things. So can...

Homework Statement Explain what you understand by the term Relative Atomic Mass The question is equal to three marks, though i don't think I've put enough for all the marks: The Attempt at a Solution The mass of an atom relative to one atom of carbon-12. I would think that's only...

Hi, i am self studying quantum mechanics. I completed reading of "Quantum Physics_Eisberg, Resnick" and "Introduction to Quantum Mechanics - D. Griffiths". I want to study further on Atomic and Molecular quantum mechanics. Can anyone suggest me textbook on those topics? Thanks in advance.

Is the accuracy of atomic clocks in any way dependent on the speed of light? For example, if the speed of light were to speed up slightly, would that somehow speed up the frequency of oscillations of caesium used in an atomic clock? ...or would those 9 billion (or so) oscillations occur at...

Can somebody please explain for me ??

As above really

Greetings, I was wondering if a fully ionized atom would interact with a photon. Id expect so but can't seem to find any info about it. Thanks! Physics Novice

This is a very naive question. But I think, it's an important point that has been unattempted in textbooks. The question is: How far should one trust the Bohr-Sommerfeld model or the atomic shell theory for all elements in the periodic table? This question generally comes in mind, since...

Homework Statement Vapor density of a metal chloride is 66. Its oxide contains 53% metal. The atomic weight of the metal is ? Homework Equations vapor density = 0.5 * molar mass The Attempt at a Solution Using the above formula, I found the molar mass of the metal chloride as...

with synchronization what the gps receiver does is compute time difference between his current time (synchronized with atomic clock onborad each satellite) and the time tag of a satellite when the signal was sent. This difference gives the travel time of an signal from the satellite and hence...

Homework Statement A small particle of mass m moves in such a way that P.E.=-1/2mk(r)^2, where k is a constant and r is the distance of the particle from the origin. Assuming Bohr's model of quantization of angular momentum and circular orbit, r is directly proportional to: (a)n2 (b)n...

Hello! I was thinking about what would happen if an atomic gas was allowed to expand in vacuum and concluded I don't have much of a handle on the subject, so if anyone would help me out - I'd really appreciate it. So, let's say we have an ideal gas in a container located in vacuum...

Hi, I am interested to know if photoelectric effect happens in a "single atom" of say Iron which is in a vacum... ? if yes, what is the workfunction of Fe2+ ? If no what is the ionization energy of Fe2+ in eV? Thanks in advance.

As a layperson...(Who is trying to understand the atom in a bit more detail). In the past, I have most often seen the atoms drawn with electron clouds that have bands of varying density. I understand the density of the bands represent areas of higher probability. I have often seen models...

Homework Statement Hey guys, I'm studying AS level physics at the moment in the UK and I'm having a hard time grasping the concept of the ground state of an atom, so my question is: Is the ground state the energy level that is closest to the atoms nucleus or is it the energy level that a...

I'm sure everyone here will be familiar with the usual graphic or image used to show what an atomic nucleus might look like. Here are two typical images used today; --------- Everybody has seen those images. But in reality, we have no picture of an atomic nucleus, we can only draw the...

Homework Statement Explain why the Zeeman effect can assist in the determination of the quantum numbers of atomic levels Homework Equations The Attempt at a Solution Not sure why this is I understand what the Zeeman effect is, and the source of the splitting on energy...

Homework Statement A neutron in an atomic nucleus is bound to other neutrons and protons in the nucleus by the strong nuclear force when it comes within about 1 fm of another particle . What is the approximate kinetic energy in MeV of a neutron that is localised to within such a region? Take...

atomic orbitals, what i just know about them is they are the regions around the nucleus where the probability of finding an electron is high and that is OK with s orbital because it is spherical. but when an electron in p orbital spins the probability of finding an electron should spin...

I've drawn up a simple system to help with my question. Suppose we prepare an atom in an excited state (| 4 \rangle in the figure), and it can spontaneously decay to the ground state (| 1 \rangle ) through either of two intermediate states (| 2 \rangle or | 3 \rangle ). Is the probability...

Hi All, I would like to ask a question on Purcell’s EM textbook on atomic polarizability. On page 362, Purcell put the relation: \underbrace {\frac{{\Delta z}}{a}}_{{\rm{dimensionless}}} \approx \underbrace {\frac{E}{{e/{a^2}}}}_{\frac{1}{{{\varepsilon _0}}}} I suspect that it...

An inflated smooth toy balloon is coated with a single atomic layer of aluminium. Esitimate the mass of Al that would be required. The density of Al is 2.7 x10^3kg/m^3 and its molar mass if 27 grams for mol. I assusmed the balloon was a sphere of radius 10cm, found surface area then...

Hi all, To my knowledge hybridization of atomc orbitals occurs only between orbitals in the same atom, with similar energies, in order to produce new atomic orbitals, identical with the same energy, to make chemical bonds with other atoms. There are sp, sp2, sp3, etc... possibilities. My...

Hi I can't seem to find any recommendations for a good atomic physics book on this site. What would you guys recommend? The level is senior undergraduate/beginning graduate physics. I have C.J. Foot's "Atomic Physics" already. Any help will be appreciated. Niles.

Homework Statement Consider phonons propagating on a one-dimensional chain of N identical atoms of mass M interacting by nearest-neighbour spring constants of magnitude C. Show that the Debye frequency can be written as w_{D}=\pi \left(\frac{C}{M}\right)^{1/2}. Homework Equations The...

Homework Statement Calculate the smallest angle (in degrees) that the total angular momentum of an atom in a 7D term can make with the z-axis. Homework Equations 2S+1LJ The Attempt at a Solution Given that the total angular momentum of the atom is defined by the quantum number J...

Hi All, I have a thought that I had a while ago and wanted some advise/feedback etc My thought was as follows: All atoms have their own specific vibration, if one was able to match this vibration or its oppisite then the bonds that hold this atom together would break apart. Kind of...

i asked to find the number of Atomic orbital of: principal quantum number(n) and the orbital Angular momentum quantum number (L) of the orbital 2s tell me if i correct n=2 and the Angular momentum L=0 ? and in the orbital 6f n=6? and L=3? thanks.

Hi, I know nearly nothing about physics, I'm a mathematician working on a computer program. Anyway, I have to write a program and my boss suggested that I use atomic units and that at the end of the program I can "scale up" to natural units if desired. I tried to read up on these units, but...

Homework Statement Natural carbon consists of two different isotopes. The isotopes have different masses, which is due to different numbers of neutrons in the nucleus; however, the number of protons is the same, and subsequently, the chemical properties are the same. The most abundant isotope...

I guess this is a FAQ, but since it constantly confused me, I'm just going to ask anyway. Two ways of exciting atoms, shoot a beam of photons and let atoms absorb them, or shoot a beam of electrons, and let atoms collide with them. However, for the excitations to happen, the former case...

Say there are two atomic clocks floating through space, both completely stationary with respect to each other. They are exactly synchronized, and not under the influence of any significant gravitating bodies. One is significantly farther ahead in the direction of motion than the other, but they...

Attached are two diagrams. One describing Moore's law, the other describing the development of atomic clocks since the 50's. Is there a connection between these diagrams, not in the strict graph-math equivalence sense, but in the sense, that conclusions regarding atomic clocks' future accuracy...

Attached are two diagrams. One describing Moore's law, the other describing the development of atomic clocks since the 50's. Is there a connection between these diagrams, not in the strict graph-math equivalence sense, but in the sense that conclusions regarding atomic clocks future accuracy...