Atomic Definition and 853 Threads

I was reading my science textbook and they have introduced the concepts of atomic mass,relative atomic mass and mass number.Here are some doubts I have- 1)Is atomic mass a ratio ? 2)1/12th of a C-12 atom is half a proton,half a neutron and half an electron.Since mass of an electron is...

I have a quiz on Tuesday at chemistry, and I began reviewing for it. The subject is the Ideal Gas Law. I pretty much got the hang of it, except that I have one tiny problem. I'm kind of rusty on chemistry, and that's preventing me from getting a good grip. I've looked on Wikipedia, but it seems...

Homework Statement Prior to 1961, the physical standard for atomic masses was 1/16 the mass of the oxygen atom. The new standard is 1/12 the mass of the carbon atom. Determine the conversion factor needed to convert from old to new atomic mass units. How did this change affect the value of the...

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...

Homework Statement Compare the energies of the 1s, 2s, 3s and 3p orbitals for both the HE and He+. For He assume that one electron is always in the 1s orbital. State any other assumptions you have made 2. The attempt at a solution I think: He can be either 1s1 2s1 or 1s2 He+ has to be...

Homework Statement Calculate the difference in wavelength between the 2p→1s line in ordinary hydrogen and in deuterium (which has a nucleus containing a proton and a neutron).Homework Equations the difference in wavelength is related with the difference in frequences with the relationship ...

I have a two questions. 1. What is the force (not energy) required to break the H-O atomic bond? 2. What is the minimum additional distance required to separate the H from the O to consider the bond broken? From this table I see that the energy of the bond is 459000J/mol and the radius of...

I am going to try traduce the problem in the best way i can. What is the minimum distance that protons of a 1 MeV bundle that collides in a gold leaf can approach to the atom core. Solution: 1.14 x 10-13 m I am posting these problem because i do not have any idea how to start...

Homework Statement The question goes something like this: What % of inter atomic separation is the root mean amplitude. The data given is: Inter atomic separation : 0.29nm , T =300k , D = 20 N/m , Aluminium atomic weight 27 g/mole. How do I proceed I have no idea on how to relate mean...

Say a core collapse event of a massive star occurs, forming neutron star matter in its core. However, the explosion manages to eject enough core mass such that the remnant is below the Chanrasehkar limit. At this point, gravity would no longer be able to overcome electron degeneracy pressure...

One atomic mass unit = .001660565 x 10-24 grams One gram Hydrogen / .001660565 x10-24 grams = 6.02 x 10 26 ? This should be Avogadros number 6.02 x 1023 what is the mistake here ?

Homework Statement Calculate the numerical value of the energy difference between the 2P 3/2and the 2P 1/2 states in Hydrogen (the fine structure). Homework Equations possible relevant equations are in the attachement The Attempt at a Solution It is quite unclear weather the...

Homework Statement Two isotopes of a certain element have binding energies that differ by 5.03 MeV. The isotope with the larger binding energy contains one more neutron than the other isotope. Find the difference in atomic mass between the two isotopes.Homework Equations 1u=931.5MeVThe...

hi guys i was wondering how the coordination numbers for the atomic positions of atoms in crystals such as NaCl are derived ...more specifically why is Na at (0,0,0) and Cl at (1/2,1/2,1/2) and not (0,0,0) and (1/4,1/4,1/4) of course this is in fractional coordinates

Hello everybody, I'm not sure if this post is more appropriate here or in the physics section (it's about biophysics topics): if it's off-topic here, please excuse me and move it. I was wondering if it's possible to calculate the enthalpy of formation of a gas molecule, in this example...

What is a good intro to atomic physics book that gives a good physical picture of what's going on.

Hi, Explain in terms of the number of nucleons and the forces between them, why argon-36 is stable and argon-39 is radioactive. My first doubt regards the number of nucleons. If a nucleon is the collective number of neutrons and protons, if we take carbon 12 for example, does it have 6 or...

Homework Statement Given: 5x10^21 Phosphorous atoms/m^3 in solid solution in silicon Find: atomic percent and weight percent of Phosphorous atoms The Attempt at a Solution I know how to solve for at. % and wt. % when given two values, I am not sure how to get the second value given the...

If it is electrical, why is there attraction between atoms? Shouldn't they repel each other due to outer electrons?

Let say we would like to perform such experiment: Let we have 2 small/mobile atomic clocks on a hard rod. (AC1)==============================================(AC2) Distance between clocks about 2 meters. There is no any electrical wire connections between these two clocks for...

I have always been told that scientists such as Mendeleev used atomic mass to list the known elements of their time. I have always been curious as to how those early scientists actually determined the atomic masses of those known elements. What kind of experiment or process/principle was used...

I have a confusing question mainly due to my lack of understanding of Quantum Mechanics and spin! here it goes anyway... In an atomic orbital, like the 1s orbital, two electron waves with opposite spins occupy the same area of space. Now, does this mean that their waves should interfere with...

http://physicsworld.com/cws/article/news/31068 I thought only elctrons could be entangled but now atoms and even ions can be entangled. Would this suggest that it could work its way to the macro levels. Could two diffrent rocks or soccer balls become entangled?

I got a question : Why is the nucleon of Chlorine 35.5 ? Why is is not a whole number ?

Hello, This question is a theory question: I have calculated the moles of molecular iodine in a problem (I2) and the next question asks to calculate the moles of atomic iodine. Do I just multiply the number I have by two (as iodine is a diatomic molecule) or is it a "trick" question and the...

When 2 atoms bond, do all their atomic orbitals combine, or is it just the bonding orbitals that combine? For example when sodium and chlorine bond, do all their orbitals combine or is it just sodiums 3s orbital that combines with chlorines 3p orbital?

Homework Statement The relative population of two atomic population states in equilibrium is given by Boltzmann Distribution: n1/n0 (proportional to) e^(-ε/(κT)) , where ε is the energy difference between the two states, T is the temperature and κ is the Boltzmann constant = (1.38 x...

hi, this is my first forum post, i hope it is in the correct category. i was reading an article last month ... http://www.sciencedaily.com/releases/2011/09/110901142058.htm now at these small distances that can be measured is the hindenburg principle of uncertainty being encroached upon...

Uh, I don't know if this suits the topic, but I've been wondering about this. Are we more times bigger than the smallest particle we know about than we are smaller than the large stars?

So I usually use VESTA to make my figures, and though the new version is able to do many mad things with calculated electron density isostructures and whatnot, I can't seem to just be able to throw in some clover-leaf d or p orbitals like what was done in the image below (from this paper on...

Does anyone have information on how exactly a atomic clock works? I have had advanced quantum mechanics courses so I am sure I wil understand it. My problem is that I can't find any descriptive materials (with drawings), the wikipedia page is very vague about the different things. So can...

Homework Statement Explain what you understand by the term Relative Atomic Mass The question is equal to three marks, though i don't think I've put enough for all the marks: The Attempt at a Solution The mass of an atom relative to one atom of carbon-12. I would think that's only...

Hi, i am self studying quantum mechanics. I completed reading of "Quantum Physics_Eisberg, Resnick" and "Introduction to Quantum Mechanics - D. Griffiths". I want to study further on Atomic and Molecular quantum mechanics. Can anyone suggest me textbook on those topics? Thanks in advance.

Is the accuracy of atomic clocks in any way dependent on the speed of light? For example, if the speed of light were to speed up slightly, would that somehow speed up the frequency of oscillations of caesium used in an atomic clock? ...or would those 9 billion (or so) oscillations occur at...

Can somebody please explain for me ??

As above really

Greetings, I was wondering if a fully ionized atom would interact with a photon. Id expect so but can't seem to find any info about it. Thanks! Physics Novice

This is a very naive question. But I think, it's an important point that has been unattempted in textbooks. The question is: How far should one trust the Bohr-Sommerfeld model or the atomic shell theory for all elements in the periodic table? This question generally comes in mind, since...

Homework Statement Vapor density of a metal chloride is 66. Its oxide contains 53% metal. The atomic weight of the metal is ? Homework Equations vapor density = 0.5 * molar mass The Attempt at a Solution Using the above formula, I found the molar mass of the metal chloride as...

with synchronization what the gps receiver does is compute time difference between his current time (synchronized with atomic clock onborad each satellite) and the time tag of a satellite when the signal was sent. This difference gives the travel time of an signal from the satellite and hence...

Homework Statement A small particle of mass m moves in such a way that P.E.=-1/2mk(r)^2, where k is a constant and r is the distance of the particle from the origin. Assuming Bohr's model of quantization of angular momentum and circular orbit, r is directly proportional to: (a)n2 (b)n...

Hello! I was thinking about what would happen if an atomic gas was allowed to expand in vacuum and concluded I don't have much of a handle on the subject, so if anyone would help me out - I'd really appreciate it. So, let's say we have an ideal gas in a container located in vacuum...

Hi, I am interested to know if photoelectric effect happens in a "single atom" of say Iron which is in a vacum... ? if yes, what is the workfunction of Fe2+ ? If no what is the ionization energy of Fe2+ in eV? Thanks in advance.

As a layperson...(Who is trying to understand the atom in a bit more detail). In the past, I have most often seen the atoms drawn with electron clouds that have bands of varying density. I understand the density of the bands represent areas of higher probability. I have often seen models...

Homework Statement Hey guys, I'm studying AS level physics at the moment in the UK and I'm having a hard time grasping the concept of the ground state of an atom, so my question is: Is the ground state the energy level that is closest to the atoms nucleus or is it the energy level that a...

I'm sure everyone here will be familiar with the usual graphic or image used to show what an atomic nucleus might look like. Here are two typical images used today; --------- Everybody has seen those images. But in reality, we have no picture of an atomic nucleus, we can only draw the...

Homework Statement Explain why the Zeeman effect can assist in the determination of the quantum numbers of atomic levels Homework Equations The Attempt at a Solution Not sure why this is I understand what the Zeeman effect is, and the source of the splitting on energy...

Homework Statement A neutron in an atomic nucleus is bound to other neutrons and protons in the nucleus by the strong nuclear force when it comes within about 1 fm of another particle . What is the approximate kinetic energy in MeV of a neutron that is localised to within such a region? Take...

What I know is that we can determine the grazing angle at which has maximum diffraction intensity, and then apply Bragg's law. But at first we have to know where is the atomic plane, otherwise the grazing angle cannot be defined. So if I have an unknown crystal, how do we actually locate the...

atomic orbitals, what i just know about them is they are the regions around the nucleus where the probability of finding an electron is high and that is OK with s orbital because it is spherical. but when an electron in p orbital spins the probability of finding an electron should spin...