Atomic Definition and 853 Threads

How to explain transmission, reflexion, refraction and diffraction at a atomic level. For example: 1 - how does light passes through a transparent material? 2 - what happens in the boundary of separation of two materials for light to be: partially reflected, partially refracted ad partially...

Why are the atomic weights of elements not integers and how many grams would there be in 1 amu (atomic mass unit) of a material? I know these are trivial questions but it's been a long time since I left school! Thanks. -SK

Oh god, please help... 1. Describe the attraction forces between atomic solids. Upon what factors do the strength of these forces depend? 2.Which of the noble gases would have the highest melting point? Why? :blushing:.. I'm not very good at chemistry

Kindly give me a link to some place I can study about Atomic Structure and Periodicity/Classification for IIT-JEE

Homework Statement Find the wavelength of the sodium transition 3p^{1},^{2}P -> 3s^{1},^{2}S Homework Equations E_{n,l} = -\frac{hcR}{(n - d(n,l))^{2}} d(3,s) = 1.374 d(3,p) = 0.884 \lambda = \frac{\hbar c}{\Delta E} The Attempt at a Solution Plugging the numbers in ain't...

Homework Statement In Clark's tables, the atomic masses of various isotopes are given which are decimal form. Are these experimentally obtained masses? Moreover, while writing nuclear reactions we do not use these, instead they are represented as integers. Is it just for convenience or is...

Can anybody tell me why atomic decays are usually only through electric dipole transitions, while nuclear decay often shows many different multipoles? i think that the transition rate for electric dipole transitions is much larger than for magnetic ones, but that doesn't really explain it. would...

Homework Statement I am having some trouble with this one, Suppose an atomic bomb was exploded in a box that was strong enough to contain all the energy released by the bomb. After the explosion the box would weigh: a) more than before the explosion b) less than before c) no change...

Is there a particular reason why the probability density distribution function of atomic orbitals bears a similarity to the modes on a circular membrane? Is this just a coincidence? Is it not actually that similar?

Hello, I'm Eddie and this is my first post here. I'm almost a Junior in college going for a B.S. In chemistry but I must say that time dilation is one of the most interesting things in science. I was wondering if anyone has actual figures with regards to the difference in time between a...

Lets say that you took a Hydrogen Atom and expanded it to the size of let's say a basketball. I am not just saying the atom itself but the nucleus. If the nucleus expanded to the size of a basketball; how would the electron size up porportionally. Now keeping it all porportional what would the...

Homework Statement What is the de Broglie wavelength of an ^{14}\mbox{N} atom that has been laser cooled to a temperature of T=77K. The Attempt at a Solution This is a trivial problem, and I can do the physics... But how do I calculate the mass of ^{14}\mbox{N}? My chemistry is obviously...

Are integers such as n=1,2,3 etc in Bohr's atomic theory, exactly whole numbers or just very close to being whole numbers?

It's interesting that TV series these days are adding suspense to the show by adding the threat of atomic bombs and nuclear explosions. But have the writers done their homework? Is this stuff anywhere near plausible? I'd like to know other peoples' opinions. Example 1, "24" An unmanned...

Hi Physics Forum. I've a question and hope you guys could give me some advice. I've been offered the chance to pursue a Phd in the field of atomic physics. The project involves investigating the spectral properties of Helium atoms using semiclassical techniques. It seems the project will be...

1: Why are the elements of a basis set taken to be orthogonal? But in real sense atomic orbitals do overlap.

As I understand it, electrons orbit a nucleus in a sort of spherical "cloud", kept in tow by said nucleus' protons. However, when two or more atoms combine, what keeps the negative charge in the electron "clouds" from simply pushing them apart?

Homework Statement Hi, I'd doing question 1 of the attached sheet and just wondered if someone could help me out. I'm a bit unsure of my calculus and need it reviewed, alsoam not entirely sure how to break down my workings (using the supplied equations in the hint) to find C. So any input...

Homework Statement A molecule with angular momentum L and moment of inertia I has a rotational energy that can be written as E=\frac{L^2}{2I}. Assuming that angular momentum is quantized according to Bohr's rule L = n\hbar, find the wavelength of the photons emitted in the n=2 to n=1...

Homework Statement To study the structure of the lead nucleus, electrons are fired at a lead target. Some of the electrons actually enter the nuclei of the target, and the deflection of these electrons is measured. The deflection is caused by the charge of the nucleus, which is distributed...

I recently purchased a new book that reviews most historical models of the atomic nucleus: http://www.brownstationers.com/BookItem.aspx?item=9783540285694 This is the only book on this subject in the past 40+ years that gives positive review (well--any review actually) for the 1965 Linus...

Homework Statement That's the problem statement (above). I basically need help knowing which fields to cover while talking about said topic in a 5-minute oral presentation. Pretty much, what I need to talk about (specifically). Homework Equations None. The Attempt at a Solution...

I came across this looking for something else. I'm curious as to what, if any, objective reality is associated with it. http://www.rense.com/general3/8000.htm

Homework Statement which of the following mass ration is ture? Mass of alpha-particles: mass of neutrons : mass of gamma- rays equal to A. 4 : 1 : 0 B. 4 : 0 : 1 C. 1 : 1 : 1 D. 1 : 1 :0 Homework Equations nil The Attempt at a Solution I thought it's D but the...

Homework Statement 1. Which of the following statements is / are not correct? (1) In fission, two large fragments of equal masses are produced from a nuclide. (2) Natually occurring elements perform fission spontaneously. (3) 2 H2O --> 2H2 + O2 involves nuclear fission. Homework...

Homework Statement Which of the following reactions will release large amount of energy (1) Nuclear fusion (2) alpha - decay (3) Nuclear fission (4) gamma - decay two of the options are: B (1) and (3) only D (1), (2), (3), (4) Homework Equations none The Attempt at a...

I spent my Thanksgiving trying to solve my homework and I will need some help: 1)For fixed electron energy ,the orbital quantum number l is limited to n-1.We can obtain this result from a semiclassical argument using the fact that the larges angular momentum describes circular orbits,where...

which atom has a larger atomic radius: K+ or Ar ?

Hello, I have a few questions concerning what the atomic model currently "looks like" since the quantum revolution. I know that, since the wavefunction, electrons are in probability "clouds" and I know they are standing waves. So this would mean, technically speaking, that the electron...

sorry, I'm having trouble grasping a lot of this... i feel like i have a general understanding of what's going on but a lot of the problems are still confusing to me... this problem An element in its solid phase has mass density 1750 kg/m3 and number density 4.39 * 10^28 atoms/m3. asks...

Hey everyone! I was wondering, when orbitals are hybridized, new hybrid Atomic Orbitals (AO) are formed. Now, when these hybrid atomic orbotals bond with another atomic orbitals, are molecular orbitals formed? For example, when 2 Hydrogens bond to form H2, the 1s orbitals overlap to form 2...

Sorry if this is wrong part of the board to post in... I am taking a atomic-molcular physics class right now and we are suposed to hold a 25 minute presentation in 4 weeks on a hot topic in atomic-molecular physics. If possible Il gladly take this as a chanse to deepen my knoweledge on...

I was wondering average atomic mass is of a fully grown male human. What I mean by this is, if we consider the human body to be comprised of mainly Carbon, Hydrogen, Oxygen, Nitrogen and other trace elements like Calcium, Sodium, Phosphorus, etc. Is it possible to determine an estimate about...

Electrons are accelerated through a potential V into a cloud of cold atomic hydrogen. A series of plates with aligned holes select a beam of scattered electrons moving perpendicular to the plates. Immediately beyond the final plate, the electrons enter a uniform magnetic field B perpendicular to...

Hello all, I've been reading about laser cooling, and when they speak of tuning the laser to a atomic transition, they write this (for example) as "The laser cooling was performed on the D_2 transition (3S_{1/2} \rightarrow 3 P_{3/2})". But what do they mean by that notation? I'm clueless...

Atomic number and Orbitals 1. Does the amount of protons define the atom? The other subatomic elements just seem to distort the properties on a much smaller scale: electrons seem to only change the charge, and neutrons the stability. Basically I just need the atomic number to define an atom...

Hello folks, I would like to know whether or not the cavity axial-mode frequencies have any influence on the frequency output of the laser beam. I suppose that the atomic transition from excited state to ground state is the only occurrence responsible for the wavelength, whereas the axial-mode...

In the hydrogen atom, an electron is in the 3d state. (i) Find the orbital angular momentum of the electron (in units of n =3, l = n - 1, l = 1. L = [sqrt( l (l + 1) )]hbar therefore L = sqrt(2).hbar (ii) Find the energy of the electron (in eV). En = -13.6ev / n^2. E = - 13.6eV / 9 (iii)...

Been many years since I took general and org chem and am currently reading general chem textbook as refresher. Came across defintion of amu (atomic mass unit). Text says that the mass of the carbon-12 atom is defined to be exactly 12 amu. However, a couple of pages over, I read that the mass of...

Can a proton or netron be compressed? Why don't individual neutrons behave like mini-black holes? What about the nucleus of an moderate weight atom; how much empty space is there in the nucleus of an atom? A lot of articles refer to the gravitational pull within a black hole, but what...

Speed of Light c= \frac {1} {\sqrt{\varepsilon_0\mu_0}} Phase Velocity v= \frac {1} {\sqrt{\varepsilon\mu}} Electric Permittivity of Free Space \varepsilon_0 = 10^{7}/4\pi c^2 \quad \mathrm{(in~ A^2\, s^4\, kg^{-1}\, m^{-3}, \, or \, F \, m^{-1})} Magnetic Permeability of Free Space...

Hello all, I wonder if anyone can help me with a problem I don't understand about atomic levels. Given an excited state of He with electronic config (1s,2p), I need to find all possible atomic levels. The answer sheet lists 4 levels: 1) S=0, L=1, J=1 2) S=1, L=1, J=1+1=2 3) S=1, L=1...

Hello How can a monochromatic light induce a transition ( absorption ) between two energy levels whose energy difference doesn't match the frequency of the incident light ?? A treatment using time dependent perturbation theory shows that the transition will occur even when the incident...

I am trying to complete some chem homework in microsoft word, but I need to write the atomic symbols. Is there any way I can write the mass number over the atomic number. Can I use sub and super script at the same time in the same place?

Quoted from http://hyperphysics.phy-astr.gsu.edu/hbase/gps.html#c1" How do they know which of the points is the correct one? (see sentence in blod) Thank you!:approve:

say an atom absorbs only a certain amount of energy. how long dose it take for the atom to release its obtained energy?

Hi all My question arises in the context of a photon which is emitted by an atom located inside a cavity. From quantum mechanics, a photon is a quantum of an electromagnetic mode, but we also use the definition which says that the photon is what is released by an atomic system when its...

hey just wondering where I went wrong Iridium Crystallizes in a face centred cubic unit call that has an edge length of 3.833A The atom in the cantre of the face is in contact with the corner atoms calculate the atomic radii of the irridium atom I did this using pythag...

Hi guys I understand that the unified atomic mass unit is defined as 1/12 of the mass of a carbon-12 isotope and has a value of 1.66 X 10^-27kg. Why is this value slightly different with when I use the calculation 0.012/6.02 X10^23? Why in theory, is the mass of a protn different from a...

I have searched some books I have on Quantum Physics, and so on, but I still haven't found any useable material to learn about the Pauli exclusion pinciple, atomic orbitals, why the Periodic Table exists, or things like that, in an informal way. Thanks, Neohaven