Atom Structure

[Guest Orange]

Hi, Im new here, and I just started to learn about atoms structure. Just wanted to expand my knowledged and understand more about biology and others..

hope this is not a dumb question, if it is, im new....hee

 

So how did scientists or chemists were able to find out the exact number of electrons/protons/neutrons in an atom?

since we can't see what an atom look like, how and what type of tools did they use to figure out these stuff?

And I don't understand why is the electron are lighter than both proton/neutrons? Since both neutron and proton are the same size, right, should the electron be the same size?

[neo007]

well firslty i think this post would be better suited in the "chemistry" or "quantum mechanics" section.

I'm not too sure how the number of electrons/protons/neutrons was discovered, but nowadays a sample can be analysed, in terms of mass, by using a mass spectrometer.

maybe this will answer your questions:

http://www.visionlearning.com/library/module_viewer.php?mid=50&l=&c3=

[ed84c]

'Exact number', well it may interest you now to know that it is generally accepted that electrons are waves apposed to particles.

 

I know some experiments show the reverse, but i personally believe we havent yet understood the results.

[swansont]

'Exact number'' date=' well it may interest you now to know that it is generally accepted that electrons are waves apposed to particles.

 

I know some experiments show the reverse, but i personally believe we havent yet understood the results.[/quote']

 

Actually it is generally accepted that they are both. Hence the QM phrase "wave-particle duality"

[swansont]

Hi' date=' Im new here, and I just started to learn about atoms structure. Just wanted to expand my knowledged and understand more about biology and others..

hope this is not a dumb question, if it is, im new....hee

 

So how did scientists or chemists were able to find out the exact number of electrons/protons/neutrons in an atom?

since we can't see what an atom look like, how and what type of tools did they use to figure out these stuff?

And I don't understand why is the electron are lighter than both proton/neutrons? Since both neutron and proton are the same size, right, should the electron be the same size?[/quote']

 

Once it was determined that the charge on the electron and proton was equal in magnitude, you know that there must be an equal number for a neutral atom.

 

Electrons are fundamentally different particles, and are not the ame size or mass as neutrons or protons. the latter are almost the same mass, but not quite.

 

To find some information, you can singly ionize an atom, so it has +1e of charge, accelerate it through a known potential difference and then let it pass through a known magnetic field. The amount of deflection you get is mass dependent (actually the charge/mass ratio), so you can measure relative masses this way and determine different isotopes. (mass spectrometer)

 

It may also be possible to completely ionize the atom and do this determination to find the net charge. If you know that you have the number of protons, and if you know the mass, you can figure out the number of neutrons.

[5614]

electrons are waves apposed to particles.

 

what swansont said + electrons have an atomic mass unit of 1/1836... so it has a mass.

[Gilded]

"Actually it is generally accepted that they are both. Hence the QM phrase 'wave-particle duality'"

 

It's fun how in the 8 shaped electron orbitals, the electron can't be at the center point (as it would occupy the same place as the nucleus or something like that?), yet it can pass through because of the w-p duality.

[ed84c]

Actually it is generally accepted that they are both. Hence the QM phrase "wave-particle duality"

 

Actually if you read my post again you would see what I think about wave particle dualitly.

[Gilded]

Perhaps we shouldn't quite go to the wave-particle function collapsing whatevergizmos. It's scaring Schrodinger's cat!

[ed84c]

I hope you dont mind, I just quoted that post in the best ever SFN quotes thread.

[Gilded]

Nah, I make such abhorring analogies and statements that it's always a pleasure to bring a dash of joy to someone.

[swansont]

Actually if you read my post again you would see what I think about wave particle dualitly.

 

And if you read mine again you'll notice I didn't comment on your opinion. Only on your statement as to what is "generally accepted."

[swansont]

"Actually it is generally accepted that they are both. Hence the QM phrase 'wave-particle duality'"

 

It's fun how in the 8 shaped electron orbitals' date=' the electron can't be at the center point (as it would occupy the same place as the nucleus or something like that?), yet it can pass through because of the w-p duality.[/quote']

 

In the "s" orbitals, though, it does spend time in the nucleus. This is why the hyperfine splitting, which is due to the electron interacting magnetically with the nucleus, is larger for s-states than for p-states.

[ed84c]

I dont want to dwell on this an distract from the thread but the point I was making was that you said 'actually....', which made it appear that you thought i hadnt mentioned WP dualitiy in my post.

[JaKiri]

I dont want to dwell on this an distract from the thread but the point I was making was that you said 'actually....', which made it appear that you thought i hadnt mentioned WP dualitiy in my post.

 

To be fair, Swansont was utterly correct to, well, correct you. You said that the electron was a 'wave as opposed to a particle', which, in the english language, means that it is a wave but not a particle, which is incorrect. You then said that there were some opposing results which you claimed we don't understand the results off, but science disagrees. We have predicted things from particle/wave duality, and found them to be true; if you have proof that this is incorrect, please say so.

[ecoli]

The number of neutrons seen on the periodic table is the average number of neutrons, the actual number varies from atom to atom. Hence the fractions of neutrons.

[swansont]

The number of neutrons seen on the periodic table is the average number of neutrons, the actual number varies from atom to atom. Hence the fractions of neutrons.

 

It's a weighted average, by the % abundance. Also, it does not account for the mass defect. However, any problem caused by that is often mitigated by the neutrons' and protons' masses being slightly larger than 1 amu.