Atom Definition and 999 Threads

Consider the pairing term in Weizsäcker formula. Here https://en.wikipedia.org/wiki/Semi-empirical_mass_formula#Pairing_term it is claimed that: I don't understand how Pauli exclusion principle should be the cause of this. This term comes from spin-spin interaction (or "coupling"), but I do not...

Hello all, I have a question. Consider an electron in a shell of an atom has energy as 1.0ev and in the next shell it energy should be 2.7eV and the further next level energy is let's say 3.1eV. Means an energy gap of 1.7eV is their between first and second level and an energy gap o 2.1 eV is...

Homework Statement Real atomic nuclei are not point charges, but can be approximated as a spherical distribution with radius ##R##, giving the potential $$ \phi(r) = \begin{cases} \frac{Ze}{R}(\frac{3}{2}-\frac{1}{2}\frac{r^2}{R^2}) &\quad r<R\\ \frac{Ze}{r} &\quad r>R \\...

Homework Statement Exact spin symmetry in the Dirac equation occurs when there is both a scalar and a vector potential, and they are equal to each other. What physical effect is absent in this case, that does exist in the Dirac solution for the hydrogen atom (vector potential = Coulomb and...

Does anybody know who first drew (not just described but actually drew, even roughly) a model of the atom like the one below, and when: I'd appreciate it if anybody can point me to an evidence.

I need to calculate the energy of the ground state of a helium athom with the variational method using the wave function: $$\psi_{Z_e}(r_1,r_2)=u_{1s,Z_e}(r1)u_{1s, Z_e}(r2)=\frac{1}{\pi}\biggr(\frac{Z_e}{a_0}\biggr)^3e^{-\frac{Z_e(r_1+r_2)}{a_0}}$$ with ##Z_e## the effective charge considered...

Homework Statement Assume that Planck's constant is not actually constant, but is a slowly varying function of time, $$\hbar \rightarrow \hbar (t)$$ with $$\hbar (t) = \hbar_0 e^{- \lambda t}$$ Where ##\hbar_0## is the value of ##\hbar## at ##t = 0##. Consider the Hydrogen atom in this case...

I shall calculate the 2p → 1s transition energies for hydrogen, deuterium (one proton plus one neutron in the nucleus), and positronium (bound state of an electron and a positron). My problem with this exercise is that I couldn't find a formula to calculate the transition energies. Can someone...

Suppose you have an experiment that measures the property of an atom as a whole, maybe you can put it through a double-slit or measure its spin, whatever. Presumably that will collapse the wavefunction that you used to describe the atom in that experiment. Would this entail that in the process...

Which one is correct below 1. a single molecule of H2O 2. a single atom of H2O (if this one is correct then what does it mean?)

Atoms make up all the material stuff around us, but most of an atom is empty space. The nucleus at the centre of an atom (99.95 percent of its mass) is orbited by tiny electrons (only 0.05 percent or less of the overall atomic mass). And as you've probably heard, an analogy is to think of the...

under what condition should the Bohr atom behave classically?

How come atom was proven to exist just because the electron was discovered in 1874, atom was like a fad of truth on early 1800s right, where atom was pictured at that time like a small brick of ball and nothing else (no electrons, neutrons, protons, parts, etc) and on that year also, chemistry...

Homework Statement Question a) Briefly describe the Rutherford model of the hydrogen atom and mention any inadequacies that it might have. b) Describe the Bohr model of the hydrogen atom, and indicate the significance of the quantum number 'n' in the Bohr model. Homework EquationsThe Attempt...

Am I right to say that an electron in the lowest level of an atom cannot fall into the nucleus because to do so requires it to give up energy in the process and it . does not possesses the energy at this atomic level.Electrons in higher levels can give up energy and fall to a lower level if...

I'm quite new to quantum mechanics. I have a question, I'm coding a small game with my friends and I do understand the orbitals and I've even written a function in java to simulate the probabilities of ONE of those diagrams, but I do not know my scale just yet, can anyone tell me the width of...

If you were to condense an atom or group of atoms, the gravitational force would be very large because the atom is 99.9999999999996% empty, so making it 100% full would be like crushing a pound of tin foil into the size of a pen dot. If the density is so much it would make a huuuuge...

Good day all! I have a question that has been in my head bouncing around for a while and I figured the best resource would be here as I can't find anymore related information (Or I am just looking in the incorrect spot). My apologies if this is in the wrong section I wasn't too sure where to...

I found an old paper online (1962) I think, stating that bremmstahlung occurs between different neutral atoms in collisions. Am I correct in assuming that this will result in frequencies outside of the usual line broadening mechanisms? Thanks

Why does a tungsten filament light bulb (or any heated metal for that matter) emit EM radiation (both visible and infrared) - is the EM radiation due to vibration of molecules or electron excitation?

greeting How exactly the electric force acts .The definition of force is In physics, a force is any interaction that, when unopposed, will change the motion of an object. as the electron circulates around the nucleus of the atom because of that I do not see how that force acts .

If someone, were to theoretically build a microscope that could see an atom what, would the electrons be doing?...would they be orbiting the nucleus at a steady speed or would they be popping in and out of existence in their shells in different locations due to the uncertainty principle?

How can we differentiate among the lifetimes of the excited states of the hydrogen atom? The states are: 2p, 2s, 3s, 3p

Homework Statement Homework EquationsThe Attempt at a Solution [/B] Both electrons are in 1s orbit. For taking out the second electron, I will have to put slightly more energy than 24.6eV. So, the energy required to remove both electrons should be slightly more than 49.2 eV. So, I...

Suppose the hydrogen atom consists of a positive point charge (+e), located in the center of the atom, which is surrounded by a negative charge (-e), distributed in the space around it. The space distribution of the negative charge changes according to the law p=Ce^(−2r/R), where C is a...

Quantum mechanics does a good job in describing the hydrogen atom. Are there any views either mathematically or conceptually in describing the hydrogen atom?

Homework Statement In hydrogen atom ionization H→p+e show that ##μ_H=μ_p+μ_r## Homework Equations G=μN (N is the number of particles) The Attempt at a Solution (1) I think the question should say "Find chemical potential relation AT EQUILIBRIUM", don't you think? (2) My professor said that...

Homework Statement Homework EquationsThe Attempt at a Solution E = (13.6 – 3.4 = 10.2)eV = ## \frac {hc } { \lambda } ## =1.22 * 10^{-5} cm So, the correct option is (a). Is this correct?

1. A certain type of atom has only four energy levels, as shown in the diagram. The "spectral lines" produces by this element are all visible, except for one infrared line. The quantum jump that produces the infrared line is: (see attached file) A) state 4 to 3.B) state 4 to 1.C) state 2 to 1...

Hello, The hydrogen atom Hamiltonian is $$H=\frac{p^2}{2m} -\frac{e^2}{r}\tag{1}$$ with e the elementary charge,m the mass of the electron,r the radius from the nucleus and p,the momentum. Apparently we can factorize H $$H=\gamma +\frac{1}{2m}\sum_{k=1}^{3}\left(\hat p_k+i\beta\frac{\hat...

Say you had two isolated hydrogen atoms. Because of the spherical distribution of electronic charge on each hydrogen and the net charge of 0 outside each atom, wouldn't Gauss's law dictate a 0 net electric field outside each atom? If this is the case, why does diatomic hydrogen so readily form...

Homework Statement When an electron in a hydrogen atom makes a transiton between two levels with prinicipal quantum numbers n1 and n2, light is emitted with wavelength of 658.1 nm. If we assume that the energy levels of the atom are in agreement with the Bohr model, what are n1 and n2...

[Note from mentor: this thread was originally posted in the Quantum Physics forum.] I am looking for a way to mathematically express the orbit of an electron around the nucleus of a hydrogen atom, while the atom is stationary as well as in motion. Note the orbit of the electron is 3...

My question is that why is the negative charge on the oxygen atom with the single bond, why not on the oxygen atom with the double bond? I am confused. Source: https://chem-net.blogspot.in/2012/01/simple-procedure-for-writing-lewis.html

Homework Statement A hydrogen atom is in the 7f state. What is the magnitude of its orbital angular momentum? Homework Equations L=sqrt(L(L+1)hbar The Attempt at a Solution L= Sqrt(3(3+1)Hbar) 1.41hbar (we want J*S) 1.41*1.054*10^-34 1.47*10^-34J*S

Homework Statement In the photoelectric effect it is generalley assumed that all the energy is given as kinetic energy to the electron while the atom is neglected. Do not neglect the recoil kinetic energy of the atom and calculate the kinetic energy of the photoelectron and the ionized atom and...

Homework Statement This is not a homework problem. It's an example in a textbook. 3 electrons. For ##S=3/2##, we have that $$ m_{s_1} = m_{s_2} = m_{s_3} = 1/2 $$ Therefore by the Pauli Exclusion principle, $$ m_{l_1} \neq m_{l_2} \neq m_{l_3} $$ and they take the values ##-1,0,1##...

Hi. From what I read, according to Quantum mechanics "even though it looks like objects are in definite places, when we get down to ridiculously tiny objects (like electrons) they seem to be not he in anyone place. And everything looks like a hazy clouds of probability."...

Homework Statement https://imgur.com/a/8deZc Homework Equations P(E) = ∫φ*(r)ψ(r)dr from -∞ to ∞ The Attempt at a Solution To find the probability, I know I have to use this equation: P(E) = ∫φ*(r)ψ(r)dr from -∞ to ∞ My question is, what is the energy eigenstate, φ*(r)? Is it the measured...

Does electron really vibrate to produce heat energy or is it atom in whole to produce heat?

The quantum physicists claim, that an electron has been 'smeared out' in the space around the nucleus. So it seems an electron in the atom is present everywhere at once. Is the next interpretation acceptable? The electron moves with many km/s in an extremely small space. In photography it...

Hi I'm Dan and new to Physics forums! I'm planning on posting something tomorrow on an alternate theory for the structure of an atom... I thought I would start with something light ;-) By day I'm a Product Owner and have established several successful and unsuccessful companies! I'm...

Hi Q1: I was reading about ultraviolet catastrophe and it was said that atoms were assumed to be harmonic oscillators of radiation. I believe that two harmonic oscillators could have the same frequency but different amplitudes so it would mean that two different atoms (i.e. two harmonic...

Homework Statement Homework EquationsThe Attempt at a Solution Let's consider the primitive model of atom i.e. the nucleus is surrounded by an electron cloud. Let's say that the nucleus has charge qa and it moves a distance d from the center in the equilibrium position. ## E = \frac {kq}...

Homework Statement Homework EquationsThe Attempt at a Solution ##\rho = b r \\E =\frac { k r^2} {4ε_0} \\ p ∝ E^a \\E \left ( r=d \right ) = \frac { k d^2} {4ε_0} \\ p = q d \\ d ∝ d^{2a} \\a = ½ \\p ∝ √E ## PART B ##\rho ∝ r^n \\E ∝r^{n+1} \\ p ∝ E^a \\d ∝d ^{{n+1}a} \\## For eq. 4.1 to...

If we do electrolysis, using a potassium electrolyte in water, the Na+ ions turn into Na atoms at the cathode. The question is, how long, on average, will it take for the Na atom to react with water and form a Na+ ion again?

Hey all, I am looking for a reference that derives the optical Bloch equations for a two-level system driven by two near-detuned monochromatic radiation sources. Specifically, I am looking to substantiate a result I derived by following the same procedure as for a two-level atom driven by a...

Hello! How do I find how much energy does electron radiate during one revolution if the energy radiation rate is given by Larmor Formula: dE /dt = [(− 2/3)* e2* a2]/ c3. Should I use the chain rule? At the moment I only want a hint how to solve this. With best regards

I have heard that atom can be in two places at the same time. How this could be possible?

I was reading that one of the successes of the Dirac equation was that it was able to account for the fine structure of some of the differences in the spectrum of the hydrogen atom. But the Dirac equation is about subatomic particles moving at relativistic velocities. But an electron around the...