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JacobD96
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hey guys, could anyone answer these questions


  • how do free electrons excite if they are not in atomic shells/ have ground states ?
  • is there's only one work function for a specific metal ? because say a photon didn't hit any free electrons it would hit an electron in the shell of ion/atom and wouldn't this type of electron require more energy to ionise/ emit from the surface of the metal than a free/delocalised electron, i.e. have a larger work function
  • is it only outer electron shell electrons that get excited ?
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teachercol
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They don't 'excite' , they just get more energy.

Work function energy is defined as the minimum energy needed. Yes other electrons need more.

Any electrons in an atom can 'get excited'. I prefer to think about the atom as a whole being excited and having energy levels.
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Mário
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(Original post by JacobD96)
hey guys, could anyone answer these questions


  • how do free electrons excite if they are not in atomic shells/ have ground states ?
  • is there's only one work function for a specific metal ? because say a photon didn't hit any free electrons it would hit an electron in the shell of ion/atom and wouldn't this type of electron require more energy to ionise/ emit from the surface of the metal than a free/delocalised electron, i.e. have a larger work function
  • is it only outer electron shell electrons that get excited ?
As far as I know:

  • The free electrons don't get excited, they are simply moving from the negative terminal to the positive one when a potential difference is applied across the metal
  • Don't understand this question
  • Nope, any electron in the atom can be excited to a different energy state (or even freed from the atom) if enough energy is present

I suggest looking at this
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Stonebridge
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(Original post by JacobD96)
hey guys, could anyone answer these questions


[*]how do free electrons excite if they are not in atomic shells/ have ground states ?
So-called "free" electrons don't excite.
I suspect, though, that this is not what you mean.
Electrons in the metal still need energy to escape from the surface.

[*]is there's only one work function for a specific metal ?
Yes.

because say a photon didn't hit any free electrons it would hit an electron in the shell of ion/atom and wouldn't this type of electron require more energy to ionise/ emit from the surface of the metal than a free/delocalised electron,
yes

i.e. have a larger work function
No
The work function is not a property of the electron, it's a property of the metal. It's the minimum energy required to eject an electron. Some will require more.

[*]is it only outer electron shell electrons that get excited ?
Not necessarily. If an incomimg photon has enough energy (X-ray or gamma ray maybe) it could eject a deeper electron.
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teachercol
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Nice consistency guys
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Stonebridge
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(Original post by teachercol)


Nice consistency guys
Simultaneous replies.
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JacobD96
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ok cooooool

so the work function is not neccesarily the same as the ionisation energy need to emit an electron from its ground state, just the minimum energy needed for any electron emission from that metal i.e the work function = the minimum ionisation energy
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teachercol
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Its not really ionisation. The electrons released are not the ones attached to atoms; they are the free electrons in the metal. We just refer to this as emission rather than ionisation. .
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