Atomic Definition and 853 Threads

Hi , well this is just a idea that came up when thinking about a certain problem in physics. Now it's late and I don't wan to be long but is it possible or has it been done , a device that could for example hold back lighter nuclei and let through heavier ones or vice versa? Well imagine a...

Assume we have a concentration of any specific material (in mg/M). Let's say for example: Ag (Z=47) with concentration 10 mg/M in water (H2O, Z=7.42). How can I calculate the effective atomic number (Zeff.) for the silver-water mixture if the concentration of silver was 10 mg/M for example...

Hey guys, I was doing some research and I am confused since I can't seem to get a straight answer. I wanted to know what the diameters/radii of protons and electrons are. But no place I go to agrees on the numbers. The general trend for protons is somewhere around 10^-15, but I've seen...

How is this possible if quarks are point particles?

Hello all, What is mean the Ritz Wavelengths in the NIST Atomic Spectra Database? Why the Ritz or Observed value for some Wavelength are very different? Thanks, Lil

When doing an experiment in order to observe the atomic spectra of some gas. We observe while peaking through the diffraction grating, symmetrical lines starting from n=1. Where does this symmetry arise from? Why do we see the same spectrum repeated on both, left side and right side. As if...

Something I don't understand about that experiment, or about relativity in general. Why the clock on the jet flying around the world is the slower one. I mean isn't the stationary clock moving the same speed away from the jetliner clock relative to the jetliner clock?

Homework Statement For our lab, we looked through the spectrometer to find the spectral values for Helium, which after being plugged into an excel spreadsheet, yielded an equation which I could use to find the wavelengths for Hydrogen. We were told to solve for R, which I did. However, at the...

If I use hydrogen-like orbitals for other atoms, how are the number of nodes and probability density affected?

One of the examples I was looking at had to do with diffusion of hydrogen in a Pb sheet. There is a constant concentration gradient applied, so the hydrogen is constantly diffusing. We are able to determine the concentration of the Pd matrix. We further know the atomic weight percentages of the...

Hi, I'm a little confused by the selection rules for atomic transitions. In pretty much any standard QM text, they derive the fact that an electron can't transition in an atom unless \Delta\ell=\pm1, i.e. unless the orbital angular momentum changes by one unit. Then the books go on to say that...

Atomic Hydrogen gas cloud to Star! what would be different about stars and their formation if interstellar medium only has atomic gas and nothing else? how would it affect stellar interior and energy production? My guess is that since atomic hydrogen is less massive than molecular...

Homework Statement Find the diameter of one atom of argon given that Dp = 2 where D is diffusion and p is pressure. The Attempt at a Solution molar mass of argon is 40g/mol using that for one atom can find mass in kgs. but that's its! im not given V, T or p. can put V in terms...

I read that a C12 atom has an atomic mass unit of 12 amu's. A C12 atom has 6 protons, 6 neutrons, and 6 electrons. If the mass of a proton is 1.00728 amu, the mass of a neutron is 1.00867 amu, and the mass of an electron is .000549, how can it's total amu be 12...

Homework Statement When an electron drops from the M shell (n = 3) to a vacancy in the K shell (n = 1), the measured wavelength of the emitted x-ray is found to be 0.0897 nm. Identify the element. Homework Equations E = 1240 / λ E = (-13.6 / n^2) * (Zeff^2) The Attempt at a...

I really need a good book in Atomic Physics that goes through the Hydrogen atom starting from the schrödinger equation to Transitions to Fine Structure smoothly and in details so that it is efficient. Any help is much appreciated.

Why is the energy of an atom with one electron missing greater than that of the neutral atom?

If atoms clump together through the interaction of electrons, protons and neurons to form matter, why can't gravity ( of the Earth for example),be simply described as just being the wholesale cumulative effect of all those electrons, protons and neurons of which the mass of the Earth consists...

I've been noticing that for expressions finding the nuclear radius there is a constant term r_0, that I can't seem to find an explanation for. The full term is R=r_{0}A^{1/3} That the atomic radius is roughly the 3rd root of the number of nucleons. But where is the r_0 coming from? I'm using...

Hi, I am trying to understand how electroplating works. With help of this wikipedia diagramm (http://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Copper_electroplating.svg/471px-Copper_electroplating.svg.png) I have already figured out (correct me if I am wrong) that it works something...

I'm currently working on a paper dealing with aspects of Franck-Hertz experiment, and encountered some puzzling descriptions and symbols in an article published in the past, as follows: 1. The article includes a simplified energy level scheme of mercury. This scheme includes also 7th & 8th...

Homework Statement Ground-state hydrogen atom with 12 ev kinetic energy collides head-on with another ground-state hydrogen atom at rest. Using principles of conservation of energy and momentum, show that an inelastic collision cannot occur. Therefore the collision must be elastic...

See attachment for working and details of what i have done.

Homework Statement I am basically wondering how they got to the assumption that the Ve = 2Vα. I've tried it a few times and I keep on getting that based off of their other assumptions, Ve should =0, even though I know that this cannot possibly be the case. Homework Equations Conservation of...

Hello world. I've been studying up on the fundamentals of electronics and have started with an abstract on atomic particles. My understanding is Electrons have a lighter mass and have a negative charge, Protons have a heavier mass and have a positive charge. Neutrons have a mass greater...

Hi, In quantum optics, the interaction between light and atoms is described by a Hamiltonian of the form d.E where d is the dipole moment of the atom. The picture given is basically that this is a vector and we take the the dot product with this and the electric field vector (whose direction...

hi guys, i have a basic question over the atomic excitation and it's relationship with the hydrogen like atoms. we know while excitation the electron in the ground state jump to the higher orbits. but when hydrogen or atoms containing little principal quantum numbered orbits get excited , then...

Homework Statement Two atomic clocks are synchronized. One is placed on a satellite which orbits around the Earth at high speeds for a whole year. The other is placed in a lab and remains at rest with respect to the earth. You may assume both clocks can measure time accurately to many...

Hello,everyone! I want to know if there is database which can tell me the energy level diagram of atom. I have consulted NIST Atomic database,but I can't find energy level diagram. so anybody can help me ? I WANT to get the energy leverl diagram like hydrogen atom in modern books(potential...

One molecule of diatomic hydrogen H2, passing through an electric arc between tungsten electrodes, splits into hydrogen atoms by absorbing a considerable amount of heat: H2 + 103Kcal = H + H = H2 + 103Kcal Atomic hydrogen, recombining into molecules, being unstable, after 0.5 seconds, gives a...

Hey, Here's the question Now I wanted to check if my thought process was correct and thus my formulation. Some sodium atom is initially excited, emits EM wave with stated λ and then de-excites to the ground state. However, this is Sodium so I think we approximate the energy levels...

In Rutherford's atomic model, electrons are in circular orbit around nucleus. My teacher said, "It has limitation. According to classical electromagnetic theory, the electrons are acceration and they will emit radiation and lose energy. And finally spiral into nucleus. Th atom will collapse if...

Determining the atomic number, mass number, and chemical name during beta decay! Homework Statement The image below shows the element Thorium with the atomic number listed above and a mass number of 233. This element undergoes two successive beta decays. The resulting nucleus will have an...

I understand there are a few different types, but with no luck on Wikipedia or Google I still need the atomic makeup of these alloys.

Homework Statement Suppose an electron was bound to a proton, as in the hydrogen atom, but by the gravitational force rather than by the electric force. What would be the radius of the first Bohr orbit? Homework Equations r = h^2 / 4∏^2*mke^2 The Attempt at a Solution I'm not...

How is it that these two have the same electron level array (1s^22s^22p^63s^23p^6), but K+ has bigger radius than Ar? K+ has one more proton in its nuclei than Ar, so I would expect that if both have the same electron configuration - the one with more protons in its nuclei would have the...

Optical density of an atomic ensemble and its linewidth Hi I've been thinking about something for a while now. If I take a two-level atom, completely at rest, then I can probe it with a quasi-resonant laser. The absorption of the atom is a nice Lorentzian, nothing fancy here. However, now...

Homework Statement 2 valence electron atom. n, l, s are : 5, 0, 1/2 n, l, s are : 4, 1, 1/2 Assume LS coupling and find the possible values of L and then J. Homework Equations None The Attempt at a Solution I am not really sure. All I know is there's something like, take...

Hello all, this came up in my chemistry class when our prof. showed a graph of the size of atomic orbitals (or orbital energy) in relation to the Z number (or number of protons). He did this to show that as the z number increases the size of the orbitals also decrease (because effective nuclear...

Here's what I know: Scientists used mass spectrometry to figure out the number of electrons in a neutral atom of the element. We know that if an atom has a neutral charge, the number of protons = the number of electrons - therefore, the atomic number = the number of electrons. Would anyone...

I find the expression: "In general, one can expand the atomic displacements in terms of all the lattice wave modes (resembles a Fourier series expansion)" at: https://courses.cit.cornell.edu/ece407/Lectures/handout17.pdf But I have not found the expression in any other literature. (In fact...

Hi, my question is regarding atomic radii of transition elements. When we move to the right of the periodic table (in the region of the transition elements) the atomic number increases, thus there is one more proton in the nucleus and on more electron in the atom. The nuclear charge increases...

Homework Statement My class is currently going over electronic energy levels, and the book states that an electron with a kinetic energy of 9.8eV could excited two mercury atoms (first excited state above the ground state of mercury is 4.9) to their first state above the ground state...

Determine scattering amplitude for atomic charge which is "spread" as wavefunction Homework Statement Derive the scattering amplitude and differential cross section for Rutherford scattering (done this). Now rederive the same quantities for the atomic charge which is "spread" with the...

First, it says in my textbook that in an anion, the atomic size will be larger than that of the neutral atom. It says this is because the extra electrons causes more repulsion and then increases the atomic radius. In the next chapter, it says as you move across a period [from left to right] in...

My question is this. I have been taught in every textbook, physics lecture, and chemistry lecture that the net charge of a stable atom is 0. The result of that should be a null electric field. But looking at any model of an atom since the electrons are spaced out significantly from the nucleus...

Homework Statement Determine the longest wavelength of light emitted from this atom. Homework Equations \lambda=\frac{hc}{E} The Attempt at a Solution I calculated the lowest energy of the light emitted: E_{min}=2.1(eV) Then the longest wavelength would be...

What is meant by "Early atomic models predicted...noble gas...stable" Hello, I am troubled by the following statement "Early models of atomic structure predicted that atoms and ions with noble gas electron arrangements should be stable" Is this referring to the Niels Bohr model or am I...

Why did Mendelev order the elements according to their atomic masses rather than their atomic number? Why did Mendelev not include noble gases in his periodic table?

Homework Statement https://www.physicsforums.com/attachments/51461 https://www.physicsforums.com/attachments/51462 Hi! I got stuck in studying the book "introduction to electrodynamics" written by griffith I attached the related pictures above. The page is p.161-p.162. It's concerned...