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Old Oct 13th 2013, 11:03 PM   #1
Alkane
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Energy Levels and Ionisation Energies

HI guys, just spent 1/2 an hour writing a post only for it to tell me Im not logged in. Hit back button and surprise surprise, most post it gone. Im so desperate though Im gonna try again.

Ok my question is to do with electron shells and ionisation energies. Ive tried to get an understanding of what is meant by 'higher energy levels' and why theyre called 'higher' if the electrons that exist in them are in fact less attracted to the nucleus than the ones closer. I know why theyre less attracted to them, which only makes the expression 'highest energy level' to describe, for example, the outermost energy level, slightly more confusing.

See if always thought of electrons and their gradual movement to more outer energy levels as akin to someone being attacked to a pole by a large rubber band. You walk outwards and as you get further out, the train on you gets higher and higher therefore by the time you reach, for example, the third energy level, that level requires 'higher' energy in order to keep the electron (you) there in place. So the energy level is like another pole further away that you've been able to now latch onto. However Ive now figured that those electrons in the outermost shell are not exactly waiting to spring back into the nucleus- on the contrary they are experiencing LOWER attraction to the nucleus on account of their distance away from it as well as other factors. So this is where I am now confused. Why are these further shells refrred to as 'higher' energy levels? Ill list the specific questions so there's no (more) confusion:

1.) Does the word 'higher' essentially in this context just mean 'further'?
2.) I know that an electron in a shell closer to the nucleus has higher ionisation energies than those further out, so does that mean, due to the fact they need to gain energy in order to occupy those energy levels further out (i.e 1s to 2s) that that's what is meant by the more outer a shell is, the higher its energy?
3.) Does higher energy just mean its higher because it holds more electrons and their total energies are all added up?

4.) And finally Im just trying to think of someone real-life analogy to apply to it - something whereby it is difficult to initiate a task but as you move further from the source it gets gradually easier - thus totally debunking the idea of electrons being made to work harder and harder as they move further away from the nucleus (the rubber-band attached to the pole analogy)

Could someone just explain basically also why 4s wants to get filled before 3d?

Sorry about this guys. Im OCPD and cant move onto the next phase unless I understand this section first.

God Bless

Sorry Supplementary question

Does the ionisation energy also refer to overcoming the energy that the shell has which holds the electron in its position away from the nucleus IN ADDITION to the force of attraction between the electron and the nucleus? Or is that just one and the same thing. God my head is hurting.

Last edited by Alkane; Oct 14th 2013 at 12:10 AM. Reason: New info
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Old Oct 13th 2013, 11:47 PM   #2
Alkane
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COrrect me if im wrong but would this be a worthwhile analogy?

There's a 5kg, 10kg, 15kg, 20kg, 25kg and 30kg dumbbell on the floor. The earth (gravity) is the nucleus of the atom, and the subsequent force 'pulling' the dumbells to earth is like the attraction of the atoms to the nucleus.

The heaviest dumbbell must be put on the horizontal rack (not vertical because that adds an extra variable of time and height) in order from heaviest to lightest. The heaviest MUST go on first). So we put each on.....gradually getting easier until theyre all on.

What do you think? That's the best I could come up with
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Old Oct 18th 2013, 03:03 AM   #3
cravingcatharsis
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4s gets filled before 3d because electrons want to fill in the areas of lesser energy before areas that are higher in energy. And 4s is lower in energy than 3d
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Old Oct 18th 2013, 06:48 PM   #4
Alkane
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Why does 4s have a lower energy level - and what does that even mean. I.e. what does it mean to say a shell has a certain amount of energy?

Sorry
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Old Oct 21st 2013, 03:58 AM   #5
cravingcatharsis
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Don't feel sorry sweety ! chemistry is pretty abstract and takes some effort to understand. I'm struggling in this course myself :P
anywho, there is no legit explanation for why 3d is greater in energy than 4s... ive looked through a lot of sites and couldn't find one. it's just one of those things that you need to memorize. its complex :P
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Old Oct 23rd 2013, 12:52 AM   #6
Alkane
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Originally Posted by cravingcatharsis View Post
Don't feel sorry sweety ! chemistry is pretty abstract and takes some effort to understand. I'm struggling in this course myself :P
anywho, there is no legit explanation for why 3d is greater in energy than 4s... ive looked through a lot of sites and couldn't find one. it's just one of those things that you need to memorize. its complex :P

Thankyou so much.

Ill have a question about Amine Ions for you soon, about why there's two pairs of unpaired electrons and three hydrogens attached - makes for 7 valence electrons? When last I checked Nitrogen didn't have that many anyway, once I re-read Ill phrase my question a bit better. But hey, do you know any good college chemistry dvd's? Ive gone to Maths Tutor dot com and some people say theyre pretty good. Im studying for the Gamsat next year and as an English teacher Im feeling further and further out of my league but hey......if you want something bad enough.....
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electrons, energy, ionisation, orbitals, shells



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