Atomic Definition and 875 Threads

I find it remarkable that physicists are sometimes willing to take “the anthropic principle” seriously, in any of its forms, since its explanatory power at the physical level is nil. Okay, say the universe is structured the way it is just so it can support conscious observers. That tells us...

Hi, So according to the Thomas-Fermi theory, the formula for atomic radius is R=Z^(-1/3)*(hbar ^2)/m*e^2. (in other words Z^(-1/3) times the Bohr radius) While the total energy has a Z^(7/3) dependence. I need to get this from dimensional analysis. I can get the dependence on h, m, and...

Hii, I was wondering whether there is any correlation between the energy eigenvalues of a single atom (say He) with the electronic band structure of a collection of He atoms. for example, for He atoms the lowest energy would be the ground state, with 2 electrons. So will the lowest band for a...

Homework Statement I'm writing a paper on the Manhattan Project, and as part of this paper I am asked to show: "... calculations that can help illustrate the explosive power of an atomic bomb compared to ordinary explosives."Homework Equations Released energy per fission: Q = \Deltam * c2 The...

"Told science" Hi guys! I am going to take part in a literature project, which is called "told science". You have to write a scientific eassy such as a story. For this year I was wondering to write down something about the atomic bomb. My idea was to write the best quotation on atomic bomb in...

What is meant by nuclear atomic model?

Hello, In Max Borns book Atomic Physics, in chapter 1, section 3, it reads http://books.google.ca/books?id=NmM-KujxMtoC&lpg=PP1&ots=yDc9g9R8Ky&dq=max%20born%20atomic%20physics&pg=PA5#v=onepage&q&f=false" "If we think of the molecules as billiard balls every molecule when it strikes the wall...

Like, let's say substance A, in the sun, is very hot. After the sun goes down, it stays hot, but after awhile it becomes cold. Element B, in the sun, is also very hot, but after the sun goes out, it basically becomes cold immediately. Why is this?

This is rather a straightforward question I believe, but somehow I'm not sure about the wording of it... Homework Statement Calculate g value (Landé g factor) for sd configuration in jj coupling. Homework Equations g = 1 + \frac{J(J+1) - L(L+1) + S(S+1)}{2J(J+1)} The Attempt...

1. Isn't it the Bohr atomic theory is proven incorrect, why some textbook even that publish in 2007 still use it to explain about electron movement? Isn't it should be using SPDF theory? 2. What is meant by satellite valley? 3. How is electron move in atom if not circulate in an orbital? 4...

Homework Statement 1. The Table below lists the isotopes of Pb and their percent by mass: Isotope % Mass 82p, 122n 1.37% 82p, 124n 26.25% 82p, 125n 20.82% 82p, 126n 51.55%(a) Using these data, calculate the approximate atomic mass...

Hi My textbook states that say 50 amu/atom = 50 g/mol. Which does not really make any sense. I am not sure how to get the atom unit. Since on wikipedia it says u = Molar-mass/Na Molar-mass(g/mol) = u*Na I also know that 1gram/Na = 1u

Homework Statement An equilibrium ore mixture has an atomic ratio for \frac{U-235}{Pa-231} = 3.04x10^{6} Find the half-life of U-235 from the data. The known half-life for Pa-231 is 3.28x10^{4} years Homework Equations For secular equilibrium \frac{\lambda_{2} N_{2}}{\lambda_{1}...

Homework Statement Calculate atomic magnetic moment of Ni in Bohr magneton. Given that atomic weight is 58.69, density is 8.91 g/cm^3 Atoms/moments are fully aligned in the field direction and have magnetization of 4.84 x 10^5 A/m Homework Equations The Attempt at a Solution...

Can the density of gas be changed for good, or is the change just temporary? And what increases density in gases?

Hi, I'm having problem about Atomic energy levels. Who can help me find Images about Atomic energy levels diagrams of chemical elements. Thanks^^. Example: Atomic energy level diagram of Hg: [PLAIN]http://ca8.upanh.com/15.290.19566358.Z7p0/fig1.gif You can contact me. I'm Hoang An

hi i was wondering if anybody could help me? for calculating if there's a missing part how do i solve it ? i have a picture ... how would i figure out the third part ..?

Just want to make sure if I have this correct and to ask a question, If you pass an electric field through an atom, it polarizes it the atom with a dipole moment p = \alpha E where is a constant of polarizability and E the electric field. Because of the electric field, the nucleus moves in the...

Homework Statement 5 The energy levels of a molybdenum atom are approximately: K shell ….. – 20.00 KeV L shell …... – 2.52 KeV M shell …... – 0.23 KeV i) Estimate the energy of the Kα, K\beta and Lα x-ray emissions. ii) What are the wavelengths of...

Hi all, What are the common atomic radii that are used for drawing chemical pictures? Is it the ionic or calculated or? Thanks.

Homework Statement Give the full designation (e.g. 3P0) for all possible singlet, doublet, triplet and quartet S, P and D atomic states. The Attempt at a Solution I don't understand this question at all! Up to which values does the angular momentum (supscript) and multiplicity...

Homework Statement What is the difference between nuclear fission and nuclear fusion? After answering the question proceed on to answer the next question Between Hydrogen Bomb and Atomic Bomb, which bomb causes more damage. provide you answer with reasons. Homework Equations Nuclear...

Homework Statement Naturally occurring iodine has an atomic mass of 126.9045. A 12.3849-g sample of iodine is accidentally contaminated with 1.00070 g of ,129I a synthetic radioisotope of iodine used in the treatment of certain diseases of the thyroid gland. The mass of129I is 128.9050 ...

Hi, I'm looking for any resources explaining time dilation at the atomic level. I can't find anything on it sooo If anyone could please refer me that would be helpful. kind regards

Rutherford postulated that the electrons are moving around the nucleus of the atom in circular trajectories, right? My professor said that or I believe in it or there is no more chemistry to study, because this does not agree with some law of Maxwell's theory of electromagnetism. He said...

Homework Statement Greetings everyone I have been been asked to write a 10 page essay on Quantum Energy levels in atomic, molecular, nuclear and solid state physics. My problem is that this is such a huge topic and my knowledge of quantum energy levels and solid state physics is limited...

I'm trying to understand what fire is at an atomic level. I'd appreciate it if you guys could correct me where I am wrong and fill in any gaps. 1: When you heat an object it introduces energy. 2: This energy causes the atoms in the object to jiggle around. 3: At some point introducing the...

Please help me in clearing my basic doubt We all know that positive charges are concentrated at the centre of the atom , known as nucleus and electrons revolves around the nucleus in orbits. Is it necessary to assume that orbits are circular ?

So I am reading about how an atomic clock works , So they shoot microwaves at cesium atoms and the right microwaves will cause an electron to jump up to the next energy level , are they using this to tune the microwave laser so they know what the frequency of the laser is . and when they...

Can anyone help. How do I calculate mass density of aluminium, given the atomic density of 6.04 X 10^22. I understand that Density = Mass/Volume. but the question confuses me. Thanks

Homework Statement Hi folks! :smile: This is just a conceptual question that has arisen during some reading. At one point the author states that for the reaction: CO_2 \leftrightharpoons X_{CO}CO + X_{CO_2}CO_2 + X_{O_2}O_2 where X is the mole fraction of each component at equilibrium...

Can the absorption spectrum of an atom be shifted significantly using electric or magnetic fields ? such that to turn red to blue or something ? Another question, can atoms be excited to a certain energy level by applying external fields only with calculated energy ? thanks

Atomic clock should record different time depending on their geo location: different latitude -> different rotation speed. Question: The most precise time on Earth - where is it valid? On what Latitude?

Homework Statement I am preparing a presentation on nuclear reactor technology. To demonstrate the mass-energy equivalence, I am trying to calculate the binding energy of some heavier isotopes. The problem is that, when I substitute the values that I have into the equation, I get a...

Homework Statement Given that the total cohesive energy, U, in an ionic crystal as a function of nearest neighbor distance, R, between two ions +e and -e is given by: U(R) = \frac{A}{R^n} - \frac{\alpha e^2}{4 \pi \epsilon R} show that at equilibrium: U(R) = \frac{\alpha e^2}{4 \pi...

Hi, I want to know what the important quantitative differences between the light produced by an atomic gas laser and that produced by a semiconductor laser are? I know that produced my atomic gas lasers are low power but high collimation, but semiconductor lasers seem to have higher power...

what i did: 27.40 * 0.781 = 21.4 52.9 * 0.811 = 42.9 62.6 * 0.856 = 53.59 there is a hint that says i have no idea how to get the common factor with those numbers.. btw i had no idea where i can post this in here so i posted here :X

Hey everyone, I've noticed that when paramagnetism is derived in the context of stat mech, we only consider the energy levels of the perturbation. Essentially, we take the fine structure of hydrogen, and we perturb it with a B-field, causing the weak zeeman effect to split the energy levels...

Are there any other good books such as LIM series which include solved problems on QM,Stat Mech & atomic physics ?

I can't even claim to understand 'spin' as a property (even after reading that big thread about it :P) but I'm sure with the amount of discussion that generated, this could be worth talking about http://www.ohio.edu/research/communications/spin.cfm

in an experiment we looked through the diffraction grating to see the spectrum made by a helium lamp. we measured the distance along the meter stick to the point where we saw each color. based on that distance how would you calculate the wavelength of the light that was seen? would you...

How shall diffusion of precursor atoms be treated if the core is in liquios state(as is MSR)[I mean regarding to its low volumetric density, shall we treat it as gas-liquid diffusion and is diffusion approximation or even transport theory valid for it anymore, what's the meaning of state space...

Is it possible to predict theoretically the maximum amplitude of vibration that atoms of a metallic species, like Copper, will exhibit at a given temperature?

I heard that the reason why we can't put our hands through a wall (or such a thing) is because of atomic electromagnetic forces pushing things away from each other (since after all, things are mostly empty space, and only seem solid because of the scale). I also heard that that is the same force...

Homework Statement First of all, this is my first post here, so I apologize if I format things incorrectly. I'm working on a Matlab script to evaluate the tunnel ionization rates via the PPT model given the correct set of input parameters. The rate equation I am using contains equations...

Forgive me if this has already been discussed. I've been searching and haven't found it. When summing the spin of an atom in the Russell-Saunders coupling scheme, some texts include the spin of an odd nucleon, and some don't. For example, if an atomic energy state is described as ${3}^P_{2}$...

I did not quite understand the "stimulation" part. How does the photon coming near the excited atom force this atom to emit another, identical (from the physical properties point of view) photon? More precisely, how do the stimulating photon and the atom interact?

Calculate the speed and radial acceleration for an electron in the hydrogen atom. Do the same for the Li++ ion. v = e (4pie0mr)^(-1/2) ar = (v^2)/r r ~ 10^-10 m v = 2.24 x 10^6 The book makes note that we can allow a nonrelativistic treatment since the velocity ~ .007c. And for the lithium...

How does atomic radii decrease when we move left to right in a periodic table? Though the nuclear charge increase as a result of increase in number of protons,the same increase is occurring in number of electrons.

Greetings Physics Forums! This is my first post. A physical phenomena that I know for a long time is that when an atom (let's say hydrogen) has an electron that make a quantum jump from a higher energy state to a lower it emits a photon. Suppose the hydrogen atom is isolated from the external...