No gravity at center of earth= no pressure?

[Drakkith]

What? You seem to be suggesting that cooling a substance reduces the size of its atoms/electron shells, as opposed to reducing the space between atoms. I'd want that backed up.

I'm suggesting both. I thought it was "common knowledge" that electrons around an atom were always moving between different energy levels. If so, they obviously would have to move into larger orbitals than their minimum energy levels are. The actual size of each orbital doesn't change, just that the electrons are moving to higher ones and coming back down. Is that incorrect?

 

[Studiot]

Higher energy orbitals does not necessarily means further from the nucleus.
It is the energy which is higher (greater) not the height (distance).
Sloppy use of terminology really, but very common.

Remember that for individual atoms the orbitals have different shapes (s,p,d,etc) and the shapes for molecular orbital in solids are different again.

The 'shells' are not concentric spheres.

 

[cjl]

I'm suggesting both. I thought it was "common knowledge" that electrons around an atom were always moving between different energy levels. If so, they obviously would have to move into larger orbitals than their minimum energy levels are. The actual size of each orbital doesn't change, just that the electrons are moving to higher ones and coming back down. Is that incorrect?

It's not really relevant at normal temperatures. It's true that in gases, electrons can be in higher than base energy levels, but the temperature required for a significant fraction of them to be in any state other than the base one is in the thousands of kelvin (possibly tens of thousands - it's been a while since I've done the math). It's relatively easy to calculate with the Boltzmann Equation though:

http://spiff.rit.edu/classes/phys440/lectures/boltz/boltz.html

 

[Drakkith]

Higher energy orbitals does not necessarily means further from the nucleus.
It is the energy which is higher (greater) not the height (distance).
Sloppy use of terminology really, but very common.

Remember that for individual atoms the orbitals have different shapes (s,p,d,etc) and the shapes for molecular orbital in solids are different again.

The 'shells' are not concentric spheres.

Of course. I only thought that in general an electron occupying a higher energy slot is further away from the nucleus. But I can see how they wouldn't make a significant difference in the average distance between nuclei.

It's not really relevant at normal temperatures. It's true that in gases, electrons can be in higher than base energy levels, but the temperature required for a significant fraction of them to be in any state other than the base one is in the thousands of kelvin (possibly tens of thousands - it's been a while since I've done the math). It's relatively easy to calculate with the Boltzmann Equation though:

http://spiff.rit.edu/classes/phys440/lectures/boltz/boltz.html

I see. Does that equation apply to non gasses?

 

[Studiot]

No I do not mean the interatomic distance ( distance between nuclei).

http://winter.group.shef.ac.uk/orbitron/

Please these orbital exist side by side in space, not in shells like onions.

The boltzman distribution curve gives an energy distribution, not a spatial one.

 

[Drakkith]

No I do not mean the interatomic distance ( distance between nuclei).

http://winter.group.shef.ac.uk/orbitron/

Please these orbital exist side by side in space, not in shells like onions.

The boltzman distribution curve gives an energy distribution, not a spatial one.

Electrons occupy such interesting orbitals! So are you saying that the electrons in the 2p and 6p orbitals are equidistant from the nucleus?

 

[Studiot]

It varies, but all the dumbell types (p, d) have a component right up to the nucleus where.

An interesting question is how they all co-exist in an atom with a lot of electons!

 

[Drakkith]

Easy. Because they are wavelike and have no choice!

 

[Studiot]

Because they are wavelike and have no choice!

Yes, true but still interesting.

 

[Drakkith]

Yes, true but still interesting.

Then it depends on what exactly the electrons are doing. Do they occupy the entire orbital all at once, or are they found as a pointlike object within them?

 

[DaveC426913]

Then it depends on what exactly the electrons are doing. Do they occupy the entire orbital all at once, or are they found as a pointlike object within them?

The orbital is nothing but a probability cloud. When you measure the position of the electron, it will be found within that cloud - with no indication as to what it was doing before the moment of measurement and no indication as to what it might do after the moment of measurement. The shape of the cloud simply defines the probability of where it will be found at that moment.

So, the latter.

 

[Studiot]

@Drakkith
Don't know how we got on to this but you should look up the Madelung constant

http://en.wikipedia.org/wiki/Madelung_constant

 

[DaveC426913]

This thread went off the rails around post 168, with discussion about neutrons. It should be split into a separate thread.