Atom Definition and 999 Threads

Homework Statement Calculate ##\left< \frac 1 r \right>## and ##\left< \frac 1 {r^2} \right>## and the expectation value and uncertainty of the potential energy of the electron and proton for a hydrogen atom in the given state. The given state is: $$ \psi_{2,1,-1} \left( r,\theta,\phi \right)...

I am currently studying a Foundation Program, which includes chemistry. -I can easily understand the distinguishable characteristics between ground and excited state via writing the electron configuration. -But how can an tom changes from ground to excited state ? And can an atom changes from...

I was looking at grotrian diagrams for helium and I see that there is no splitting of energy levels due to spin-orbit coupling. In my book it is said that spin-orbit coupling in helium is small and can be neglected but no further explanation is given. At the same time we do spin-spin coupling...

I've seen the equation I think is just for hydrogen. is this just for hydrogen? of course this doesn't return the atomic spectra, it returns the energy. So using E=h*v and Planck's constant. a simple factor of 1/h would return the frequency. right? Energy is directly proportional to frequency...

Homework Statement http://i.imgur.com/GQ9Xk6d.png Homework Equations Quantum mechanical model of atomic structure The Attempt at a Solution Why all sets are allowed? H atom only got one e- which only one orbital should be there, isn't it? If there aren't second or more e- , no second...

Hello, Sorry if this is a rather basic question, but my memories of solid-state chemistry are a bit rusty. Basically I'm trying to predict new crystal structures. I understand the crystallographic aspects quite well and know that at given external temperature and pressure the most stable...

Homework Statement A beam of neutral hydrogen atoms in their ground state is moving into the plane of the page and passes through a region of a strong inhomogeneous magnetic field that is directed upward in the plane of the page. After the beam passes through this field, in how many beams was...

I'm trying to find a way to understand Q.P. So far I know that each element contains as many protons as it does nuetrons or electrons. Is that right? Derp lol

hello everybody :) Let's assume that we could steal all electrons of an atom. What would happen? How would the atom change its properties? Could we measure different values?

Hello. I think excited states of Argon atom is described by j,l coupling written as (2s+1)[K]J. However, when I read some papers describing cross section data for Argon atom, data are quoted with strange notation, Paschen notation. I tried to study the Paschen notation and found that its form...

There are some software can provide visualization of crystal or protein structure, i.e. VESTA. I want to know how many atoms is the nearest neightbour (and their distance), and the next nearest neighbour...etc of a particular atom. Is there any software (or perhaps some data book?) can do this?

Homework Statement We have coaxial cabel with radius R and R0=3R filled with magnetic.Magnetization J(r)=(r3-R3)/(2R3)*I/(2*pi*r).What is the magnitization if r=0(center of atom)?And what a magnetization direction of atom? Homework EquationsThe Attempt at a Solution I think what magnitization...

Has anyone ever tried to split an atom up into each of its individual nucleon? If not, what's the closest anyone has come to? For example, if Uranium has 238 nucleons, has anyone ever tried to split it up into each and every last proton and neutron? Can anyone even do it for a light element like...

Homework Statement We have 2 laser beams counter propagating through a cavity with an atom traveling at some velocity. So one laser beam is propagating left and the other right. One laser beam has an intensity of .05*I_sat and the other 10*I_sat. The goal is to get the transmittance (or...

How many orbits are in the hydrogen atom?

I was reading Feynman Diagrams and stumbled upon this query: If the electrons and protons interact by exchange of photons, does the electron inside an atoms also interact with the nucleus with a similar kind of exchange?

I saw another post about this but i didn't quite find what i was looking for there so i thought i'd give it a go instead with a thread. Homework Statement Calculate the exact value of the kinetic energy of the hydrogen atom in its ground state. No more information is given, we are referred to...

I'm taking a module in solid state electronics and I'm a bit confused with the energy band diagrams. I was told that the region between the top of VB and and the bottom of the CB is the "forbidden gap". However after learning about N-type semiconductors(silicon), I see that the extra electron...

Homework Statement By substituting R(r)=r^2*e^(-r/a) into the radial equation for a hydrogenic atom, find the values of a, ℓ and E for which the function R(r).Homework Equations http://puu.sh/rOJQ3/8bcad54c45.png The Attempt at a Solution I took the first derivative of R(r), then multiplied...

Homework Statement Suppose we have a wavefunction with n=4. If we measure the orbital angular momentum along the z-direction(no spin in this problem) and get 2*hbar then what are the possible values of the total angular momentum and what is the most general wavefunction after the measurement...

I learned about pure state, mixed state, reduce density matrix, etc. from this now famous paper http://philsci-archive.pitt.edu/5439/1/Decoherence_Essay_arXiv_version.pdf (thanks to Bill) I'd like to know something. Atty said somewhere: "A pure state means that we have prepared many copies of...

Homework Statement . An atom at rest can undergo radioactive decay, ejecting an electron at a maximum speed of 0.5c. If the atom in a particle accelerator is observed to produce an electron traveling at 0.75c, at least how fast must the atom itself have been moving? Homework Equations u0 x...

Homework Statement Lead has a mass of 11.35 g per cubic centimeter of volume, and the mass of one of its atoms is 3.439×10-25 kg. If the atoms are spherical and tightly packed, what is the volume of an individual atom? ( m3) Homework Equations conversions The Attempt at a Solution For this...

What would happen to an atom or molecule if you put it in a vice and tightened the vice as tight as possible?

HI guys! I was thinking... What would happen if the atom were considered the smallest thing of the universe, or just that electrons, protons e neutrons were that? That would impact in semiconductors technologies? Or plasma? Or nanotech? How? Thanks in advance.

How would you solve the Schrodinger equation for an electron in an atom. What potential do you use? Thanks!

If you have a pair of particles (perhaps atoms for example) that are entangled, and one of them is mixed in amongst a whole bunch of other atoms of the same species, yet not entangled; could you differentiate in some way the entangled atom from the rest WITHOUT destroying the existing state of...

Homework Statement Predict the hybridization and geometry of the indicated atom. Answer all parts. Homework Equations CH3CH2 There is a ( - ) sign above the second C Hybridization = ? Geometry = ? The Attempt at a Solution I know I'm supposed to count the groups around the atom, but I'm...

Homework Statement On which orbit of hydrogen atom an electron has the speed of 734 km/s? Homework Equations Bohr's second postulate: mvr=nh,m=9.109\cdot 10^{-31}kg,v=734 km/s,h=6.626\cdot 10^{-34} m^{2}kg/s The Attempt at a Solution By using the second Bohr's postulate, we get 6686.006\cdot...

Hello, I was building some test crystal structures with VESTA software and I noticed when generating the POSCAR output files to be read by VASP that for a simple monoatomic basis such as in elemental silicon crystals some distinct space groups produce the same exact POSCAR files (i.e. same...

I'd like to see some 3D visualizations of what the wave functions of the electron and proton in a hydrogen atom would look like in different applied electric fields. Say, have a reference image at 0V, then images at various voltages where the wave functions look interesting or just illustrative...

Homework Statement The orbit of an electron (-e) around a nucleus (Ze) is a circular orbit of radius a in a plane perpendicular to a uniform magnetic field \textbf{B}. By writing the equation of motion in a frame rotating with the electron, show that the angular velocity \omega is given by one...

Hi, I read in some papers which say the unit of atom scattering factor is e/atom. what is the meaning of that? thank you!

The Dalton's atomic theory states that atoms can neither be created nor destroyed. Then how was the first even atom created in this blank space? Is it physically possible to create an atom?

Hi there, I took the course of quantum mechanics long time ago. From there I learn how to describe an atom with wave function. For example, Hydrogen has the wave function in (spherical coordinates) space. In the book they consider a reduced mass for the nucleus and the only external electron...

This website here says that the expression for binding energy for an electron is: This http://ocw.mit.edu/high-school/chemistry/exam-prep/structure-of-matter/atomic-theory-and-atomic-structure/MITHFH_lecnotes05.pdfby MIT calculates it quantum mechanically to give: The book I was reading...

Homework Statement We model the Hydrogen atom as a charge distribution in which the proton (a point charge) is surrounded by negative charge with the volume density of ρ = -ρ0 * exp (-2r/a0) where a0 is the Bohr radius. And ρ0 is a constant chosen such that the entire atomic distribution is...

Metals have a work function which is the minimum energy needed to ionize an electron. I assume that the energy need is simply the energy difference of the two highest energy levels of a particular metal. This is all well and good and can be accomplished by absorbing a photon of that specific...

Hi, Does an Atom's Type have to do with the number of protons and neutrons it has? Or are they completely unrelated? Just curious. Thanks :)

Homework Statement [/B] My question is more about the math of the problem. For equation 22.97, how do I construct a 3x3 matrix from a 12 element series? After constructing the matrix should I set the determinant equal to 0 where I will find the determinant has 3 solutions (2 being...

My teacher posted on his website, Lewis structures of different compounds. One of them were N3- Why isn't there a dipole moment arrow pointing from the central atom to the other Nitrogen? Does the arrow only point from neutral atom to negatively charged atom?

Homework Statement When an instable atom emits alpha or beta particles. Doesn't the overal electrical charge of the remaining atom change? For example when an atom emits alpha decay, a helium core is emitted, this results in the lose of two protons (forthe radiating atom). But doens't this mean...

What is the function that describes the shape of this Bremsstrahlung X-ray spectrum curve? Ignore the characteristic "spikes".

I am trying to calculate the Lyman-alpha wavelengths of photons emitted from different hydrogen-like atoms such as deuterium and positive helium ion 4He+, using the relation 1/λ = R*|1/ni^2 - 1/nf^2|, where R is the Rydberg constant and ni and nf are integer numbers corresponding to the initial...

Beam standard atomic clocks work by changing the magnetic state of a cesium atom by applying a microwave frequency that matches the resonant frequency of a cesium atom. What is this resonant frequency of the atom in terms of actual events that occur on the atomic level...

Homework Statement The equation for the normalized ##n=3##, ##l=2##, ##m=0## wavefunction is given by $$\psi_{320}=\frac{1}{81\sqrt{6\pi}}\left(\frac{1}{a_0}\right)^{3/2}\left(\frac{1}{a_0^2}\right)r^2e^{-\frac{r}{3a_0}}(3cos^2\theta-1)e^{i\phi}$$ Determine the expectation value ##<r>##...

Homework Statement When a photon is emitted by an atom, the atom must recoil to conserve momentum. This means that the photon and the recoiling atom share the transition energy. (a) For an atom with mass m, calculate the correction Δλ due to recoil to the wavelength of an emitted photon. Let λ...

Homework Statement The difference between Rutherford's and Bohr's theory of atom is ... A. Bohr's spectrum of hydrogen atom is discrete while Rutherford's continuous B. Bohr's stated electron goes around the nucleon while radiating energy, while Rutherford's not radiating energy. C. Bohr's...

Homework Statement The 3s state Na has an energy of -5.14 eV. Determine the effective nuclear charge. Homework Equations ##Z_{eff} = Z - s## Where Z is the atomic number and s is the number of shells in inner orbits. The Attempt at a Solution The textbook doesn't go into much more detail...

If we were to assume that the electron moves around the proton with radius a, the Schrodinger equation becomes: ##\frac{1}{a^2}\frac{d^2\psi}{d\phi^2} + \frac{2m}{\hbar^2}|E|\psi = 0## The question in my textbook asks me to solve the above equation to obtain values of energy and angular...