Atoms Definition and 853 Threads

A plasma is when electrons become unbound by their atoms. So does that mean that you can get a different plasma for all different types of atoms (like gold plasma and helium plasma)? Also the electrons are not free as they are bound to the plasma (but not individual neuclei) by the magentic...

Quantum numbers of atoms in a given state "(number^number)letter" Homework Statement An atom is in the state 42F. Write down the values of n,l,s and j. Homework Equations The Attempt at a Solution n=4 l=3 I'm having problems with s and j. I know j=l+s, does one...

Homework Statement In outer space the density of matter is about one atom per cm^3, mainly hydrogen atoms , and the temperature is about 2.7 K. Calculate the rms speed of these hydrogen atoms, and the pressure (in atmospheres). Homework Equations.5mv^2 = 3/2 KT The Attempt...

Homework Statement In outer space the density of matter is about one atom per cm^3, mainly hydrogen atoms , and the temperature is about 2.7 K. Calculate the rms speed of these hydrogen atoms, and the pressure (in atmospheres). Homework EquationsPV = NkT The Attempt at a...

Firstly be easy on me, I'm 17 and still in high school and English is not my first language so go easy on the heavy vocabulary. I was wondering the other day, what is it that gives atoms its properties? If air would be densed to as thick as water, would it have the same properties? I don't...

HI, I want to reproduce results from the article (attached). I need to get parameters of interaction between atoms of H2 and C6H6 for Morse equation. I easily got results of interation between MOLECULES H2 and C6H6, shown in Table S2 'The first-principles and Morse force field (eq.1)...'...

So I've seen radial equations for Hydrogen out there (eg http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hydrad.html), where can I find one for more any arbitrary atom? admitedly, I realize that the equations become more and more complicated the larger the atom is. This is especially...

2.3 \cdot 10^{10} atoms decay via alpha emission have a half-life of 150 min. How many alpha particles are emitted between t=30 min and t=160 min? \begin{flalign*} 150 &= \frac{\ln 2}{\lambda}\\ \lambda &= 0.046 \\ \\ K &= K_{0}e^{(-\lambda)(t)}\\ &= (2.3 \cdot 10^{10})e^{(-0.046)(30)}\\...

So, I was brushing my teeth and started thinking about pi and how it is irrational. One thing led to another and I remembered Atom, by Asimov (which I haven't yet finished). Now, assuming pi is irrational, if we have a wheel with a radius of 1/2 (units don't really matter), and unroll it so that...

I've been looking at the original Herman-Skillman program that solves for the energy levels of a single atom using Hartree-Fock with Slater exchange orbitals. There is one part I can't understand: the expression of the correction to the energy level for a good guess. What the program *does* is...

I there,i am new of the forum, i was wonder if atoms die or get old... For example,if i drop a piece of paper on the ground in a bit of time it will be destroyed right?by the atmosphere and weather condition,but this mean that the atoms will no be there anymore?that mean that the strong bond...

I have a question which I would like to know the answer to, I posted it before but don't think I was understood correctly, hopefully I can make myself clearer this time. Every physical object in this universe has a natural or resonant frequency from an atom to a planet. Attached is an image of...

Hi guys As far as I have understood the technique of optical puming (OP), then if we look at the hyperfine state F=2 (for example), then OP can be used to prepare the atoms in the state F=2, mF=2, but not any other (i.e., lower) mF. Is there no technique for preparing atoms in a state with a...

Homework Statement The potential energy of two atoms with a radius r is written as- U(r)= -4Uo[(Ro/r)^12 -(Ro/r)^6] Find the radius at stable equilibrium and the work required to separate the two atoms. Homework Equations F(r) = -dU(r)/dr The Attempt at a Solution If...

hi, I asked myself: how can something like superfluidity exist between atoms, when there should always be van der waals forces and therefore an interatomic interaction? so imho there should always be this kind of friction between the atoms. where am I wrong?

Is this why? The atoms of each element vibrate at different oscillations. Which means that not all elements atoms vibrate at the same type of light etc. When EM radiation hits the atom, some it it hits the electrons and the energy is transferred into the electron, since the electron has...

I am told that when an atom absorbs a photon, it jumps up an energy level, these are discrete levels of energy etc etc. What determines how long the electron will hold this energy, and what exactly is the photon (wave) doing to up it's energy level. For ease of explanation, let's assume Neon...

1. Question: In one region of a nebula the mean separation of atoms is 2.3x10^-3 m. What volume of the nebula contains enough atoms to make a star, similar to the sun, of radius 7.0x10^8 m within which the mean distance between atoms is 1.0x10^-10m? 2. Volume of sphere 4/3(pi(r^3 ))...

Hi, is there the concept of light in an Atom??

I just wantedhow the atoms vibrate in solids. I do not want to know the reason of their vibration (I know it). I just want to know their pattern of vibration. Some people say that they vibrate by undergoing a to and fro motion. But I do not think it is true because the objects are three...

Hi If I have a gas of atoms that emit light, is it accurate to regard the gas as being a thermal source? Niles.

What an Atom in say a lump of steel in melted to molten metal, what happens to the Atoms ? Surely they melt and are destroyed, or do they reform ? As I thought everything was made of Atoms ? Are water and such made of Atoms ? Wayne

At what speed do atoms start tearing apart? (The paragraph bellow tells why I want the answer to this question.) According to Stephen Hawking, when an object approaches the speed of light, the natural forces causes time to slow down so no matter how fast an object goes, it can...

Homework Statement Given a volume of Al2O3, how many atoms of each element? Homework Equations The Attempt at a Solution

Homework Statement The degeneracy of the nth level above the ground state for a three dimensional harmonic oscillator is (n+1)(n+2)/2 where n takes values n=0,1,2,... A gas of N non-interacting identical lithium atoms (mass 6amu) each having spin1/2 is confined in a 3d harmonic potential...

Given two people of different complexion, one short and chubby and the other one tall and thin, but same weight (180 lbs each): a> Do they have the same number of atoms in their bodies b> If not, will the percent difference be significant? c>Is there a way to know an estimate of this...

Can someone post a picture of 2 bonded atoms... But not those googled ones. I am trying to understand how does that look at molecular level. Why would 2 atoms bond to form a molecule. eg. hydrogen, covalent bond. I know now 2 atoms of hydrogen have full shell, but that electron doesn't...

In fact, why do the PE of atoms decrease when they form bonds, in terms of molecular interpretation, i.e. what actually happened in the atoms making they have lower energies?

If I have a 3 atom lattice laid out at positions ##x_1 = 1, x_2 = 2, x_3 = 3## ##x_1## and ##x_3## are stationary, but ##x_2## interacts with ##x_1## and ##x_3## via the Lennard-Jones interatomic potential. I therefore worked out that the total acceleration for ##x_2## for ##m = \sigma =...

Hi 1) As a star is composed of a huge number of atoms and molecules in the sate of gas, how is it near to reality to consider it as an ideal gas? 2) Is the energy of these atoms pure kinetic? I mean is the energy of each atom/molecule 1/2mv^2? 3) how is KT related to the energy of these...

Homework Statement The following hydrocarbons have different structures but the same atoms except for one. Which of them is this exception and what is the difference? a)cyclobutane b)1-butene c)2-butene d)cyclobutene e)methylcyclopropane Homework Equations Which of them is this...

Hi there, I'm a first timer on this forum and am hoping to get some help. Homework Statement 4.00×10^23 nitrogen molecules collide with a 18.0 cm^2 wall each second. Assume that the molecules all travel with a speed of 350 m/s and strike the wall head on. Homework Equations F...

Hello, I am apprentice in quantum physics and physics generally. When Rutherford posted his model, he was strongly negated because of the fact that electrons will fall in nucleus. Well i got that part quiet well but when i learned that planet goes around its sun mainly because inertia (losing...

Say you built a magnetic array, and two long electrodes running perpendicular to the magnetic field, whose electric field is then perpendicular both the electrodes and the array. Most magnetoplasmadynamic thrusters (built as previously described) then send current at an enormous voltage through...

Hello, Someone I know doesn't believe in atoms. I know it sounds strange: the person acknowledges that the model that is used is useful for calculations, but apparently the idea of an atom sounds "too perfect". And apparently the structure of an atom lattice is also too perfect. But aren't...

I have heard of carbon compounds in the form of rings or circles like cyclohexane and cyclopentane and it set me wondering of why carbon atoms do not form square or triangular rings. Could someone explain the reason?

Do atoms exist in a vacuum?

This is a silly doubt i guess... Homework Statement When you know an atom's radius you can easily determine its volume by considering it's a sphere. But when you're dealing with solids, that is, a set of atoms... and then you have bands insted of orbitals... this differente...

Hi, I running a full CI calculation for low Z elements (up to Ne) in order to obtain the lowest lying electronic energy levels. I can't seem to get correct results even though I'm using 1-electron states from first 4-6 electron shells. I am also using singly and doubly excited...

I can offer no further insight.

Suppose that the interaction energy between two atoms is given by: E(R)=-A/(R^2)+B/(R^10) The atoms form a stable molecule with an inter- nuclear distance of 0.3nm and a dissociation energy of 4 eV. a) Determine A and B. b) Calculate the force required to break the molecule. What is the...

Hello Could anyone help me rewrite following C code to Fortran code? It generates coords for sc silver atoms. #include <stdio.h> #include <math.h> int main(void) { int i, j, k, n = 0; double A = 4.08, L_X = 20.0, L_Y = 20.0, L_Z = 15.0; int iMax = ceil(L_X/A)...

Homework Statement Dear all, I have to calculate the mean speed of hydrogen atoms, at temperature of 50K. Homework Equations Of course: <v>=\sqrt{\frac{8k_BT}{\pi m}} The Attempt at a Solution However, when I attempt to calculate it, m=\frac{2}{6.022x10^{23}} k_B=1.3807x10^{-23}...

Correct me if I am wrong, but atoms emit photons when they jump energy levels. Right?

Hello PF readers, Could anyone enlighten me on this specific field of research in physics? I am particularly interested how new/old this field is, current developments, major theories/models/predictions motivating the research, obstacles if any, the saturation of the field? Thanks in...

Homework Statement Aluminium atoms at 1173K enter a vacuum chamber. Calculate the most probable speed for the atoms. Homework Equations vmp=\sqrt{}(2kT/m) The Attempt at a Solution The molar mass of aluminium is 0.0270kg mol^-1, so vmp=\sqrt{}(2*1.381*10^-23JK^-1)*1173K/0.0270kg...

Nuclear decay and the "age" of atoms. All atomic nuclei heavier than hydrogen were created in stars and would therefore seem to have different ages relative to some specific spacetime reference. Nuclear decay wrt a single atom is taken to be a temporally random event, but is it plausible to...

How does something become tangible? How many atoms are needed to be able to see/hold something?

If the strong force is what is used to describe the attraction in the atomic nucleus, how is it possible to split atoms without them constantly re-pairing? a free charge doesn't seem like it would exist due to the strong force. I'm missing something right?

1) where i got more atoms in 20 gr H2SO3 or in 20 mol of HCl ? 2) tell me if i Right: the mass (in gr) of 100 Molecules Of SO2(g) is: the mass of O2=31.998, the mass of S=32.065. so Together the mass is about 31.998+32.065*100=6406.3 but i don't sure how to Change it to (gr) unit...