I Need Help!!! Atoms

[bball14]

How do you find the radius of a zinc atom using avagadro's number (6.02 x 10>23), the density of zinc (7.13 g/ml), weight of 1 mol of zinc (65.4 g) and using V=4/3 (pie) r (cubed). I don't just need the answer i wanna know how to do a problem like this! THANKS

[P_Rog]

65.4 g / 6.02 x 10^23 = mass of one atom

 

7.13 = mass of one atom/ V

 

solve for r

 

oh, and it's pi, otherwise r would stand for raspberry i suppose?

[NSX]

mmm....raspberry pi

 

For questions like those, I like to use the factor label method, whereby I write all the units and try to arrange them in such a way that they cancel each other to give the desired one.

[YT2095]

the answer for the Zn radius is 0.133 nm. so maybe you can use that and try to reverse engineer the formula (maths gives me a headache).

[Gilded]

Hmmh? If zinc has a 0.133nm radius, then where does the 0.5nm average radius of atoms come from? Are the heavier elements so much wider? I'm not sure about other pages/books, but whenever I've found info about atoms, it says that the average is about 0.5nm

[YT2095]

in my list, it quotes Cs as having 0.263 nm taken from the same scale as the Zn, rellating to Radius of Atom in Metal or Non-Ionic solid.

 

Cs is the largest radii in my list

[bball14]

thank you so much for helping me out with this problem!!

[Encrypted]

Just a question:

 

If we can't see an atom. How do we know it's radius.

Or are we able to see an atom using a special microscope?

 

Encrypted

[Crash]

We know the radius because we can measure it indirectly (bond lengths) and through share theortisising, it works. we can see atoms with special microscopes (electron microscope) but cannot see it with visible light for obvious reasons. I have seeen several pictures of atoms, but theyre not much to look at really

[swansont]

Just a question:

 

If we can't see an atom. How do we know it's radius.

Or are we able to see an atom using a special microscope?

 

Encrypted

 

That was the point of the original question. If you know its density and atomic mass, you can infer the radius.

[Gilded]

Hmm... I've also wondered how large a crystal must be to be seen with bare eyes from a distance of 20cm or so; somewhere near 0.1mm in diameter if your vision is good? It would be nice to think that a really, really small crystal you can barely see consists of like ten million atoms.

 

It's also amazing how people make very small things by arranging atoms or by laser cutting. A good example is the IBM-logo, the blood cell-sized bull-statue (unbelievably natural looking) and the world's smallest ice crystal; exactly 6 molecules of H2O.

[r1dermon]

daaaamn, thats small....