# Electron cloud confusion

#### azerym

Registered Member
In my science class, we're currently doing a unit on chemistry. Today we pretty much went over the structure of an atom, and the teacher was talking about the electron levels. She said "You can have up to 18 electrons in the third ring but after eight electrons in that third ring you get into sublevels ." Can someone explain the sublevels in the electron field?
Basically, I'd like information on atomic structure. I know that within the nucleus there are protons and neutrons, and surrounding them is the electron cloud. What I want to know is how the sublevels within the electron cloud are structured and what they are.

In high school they tell you that atoms have clouds and each can hold 8 electrons except for the inner most cloud, which holds 2. Thats correct but thats also a simpler way to draw an electron. However, these clouds are not as simple as that, there are clouds within clouds, which is all you need to know. The discovery of clouds within clouds is a result of quantisizing the atom. It helps to think that energy is not continous, but discrete. Each atom also has a discrete position for electrons, which lead to the believe of energy levels. These energy levels (what we call clouds in high school) are the S, P, D, F levels, also called orbitals. The S orbital holds 2 electrons maximum, the P holds 6 maximum, the D holds 10, and the f holds 18. Remember when we said the first orbit holds 2 and the next holds "8", thats correct but we were talking about clouds. The first actually does hold 2 but the second holds another 2, and actually the third holds the 6 that makes the "8". It turns out that scientists developed a gigantic microscope to figure out the actual appearance of the atomic orbitals. Now, I can't actually tell you how to write short hand electron configs using these orbitals because its very difficult to teach someone over the internet. But trust me, its not difficult. The sad thing is a lot of books give tedius techniques and I know a better and shorter way. I'll try to explain...The first row of the periodic table is the 1s,p,d, whatever, the second row is the 2s, p, d, whatever, the third, is the 3s, p, d, whatever. please note that the D orbital starts from the forth row. Now you need to know that it goes S,P,D,F. To write an elecron config, you find what row it is and write it down. Lets write Oxygen's config, starting from the top (no shorthands or short cuts). Forget about elemenst, only see electrons! There is one row above Oxygen and that row is the S orbital, which holds 2 electrons, so we write 1 s2, then we step down to oxygens own row and write 2 s2, then we count to oxygen while skiping the transition elements from the middle, we would count 4, which means 2 p4. The first two colums are for the S orbitals, the inbetween break (transition elements) is for the D orbitals (D holds maximum 10 and the inbetween break is not accidental also 10 units), the P's start after the inbetween break(also 6 units). So oxygen is writen 1S2,2S2,2P4. Don't worry about the elements after Ar if you are in high school. Let me know if you have any problems.

http://www.webchem.net/notes/atomic...ation.htm#Evidence for electron energy levels

It's even better if you get hold of a decent inorganic textbook and look up the orbitals. Mine show S orbitals as spherical distributions of charge about a centre. P orbitals are like barbells, and there are 3 of them, arranged along the X, Y, and Z axes. D orbitals are X, Y and Z axes and the XY and ZX axes. Knowing the spatial distribution can help remember that you fill the simple S orbitals first, then the P ones.

Later on they'll talk about atoms which do not fill up S,P, D in simple order, but that is mostly a problem with heavier ones, and if your just at school you don't really need to know about it, but feel free to look it up.

If you become an organic chemist, you won't have to know that.

I seem to recall rather a lot of organic chemistry trying to work out how the reaction proceeded according to the pie orbitals of the carbon atoms. I shall have to dig out my notes to check though.

Basically the electrons can only occupy so much "real estate," so like humans or anything else they have "creative" ways of fitting more of them into a smaller space.

Could you say that a high-rise apartment complex is a "people cloud"?

Certainly! They are assigned levels, segregated into compartments much like electrons.

The complex geometry of e- clouds is a bit like this, but they are arranged based upon their interactions with different forces, the weak nuclear force and the electromagnetic force primarily.

See, people in apartments are arranged thus because of gravity (primarily) but also electromagnetism. If you try to pass through another person, you instead bump into them - and they get kind of upset at you - both are electromagnetic phenomena. Your electrons LITERALLY repel theirs and you briefly interact on a quantum level and experience the macroscopic phenomenon of "solid" matter - what's really a momentary repulsion of electrons and other particles.

So to avoid one another, people separate into units (apartments) - that's to avoid electromagnetic interaction. Because of gravity we build floors and ceilings to keep them from interacting vertically (or falling on one another.)

To sum up, electrons are doing much the same thing, only they don't exist on a planar (2 dimensional) surface - and your experience of Earth is very much planar - you live on some 2-D plane with other humans. They exist in a 3-dimensional space, so their arrangements are a bit different in appearence, but the basic purpose is the same.

They exist in the lowest energy state.

If you had some jerk sleeping 3 inches from your face, you would be in a high energy state, too!

So you move into your own private pad where your energy level can be as low as possible.

Wow thanks....and Gently Passing, I like your way of describing it.
It does make a LOT more sense now.

This topic helped me alot. I was assigned electron cloud as my oral presentation for 9th grade, however I was given no help on it and i have to find info and teach it on my own. I have to give a 2 minute speech at all. What would you guys say? Also, for the apartment analogy it helped but it also was confusing. Can somone state what its basically saying. From my knowledge I understood it as electrons cant be bunched up so they go to different orbitals to stay away from eachother, but I definitely didnt get the last part about I move to a private pad to be at the lowest energy level possible. I know that the S shape is the lowest energy level so do they all go there? Because from my previous research it showed that electrons in a hydrogen atom are more likely to be on the outside. Please help me my hw is due tuesday.

Well, i'm not a chemist... i study physics, but in physics we also need to know what electrons are, how we stack them up and their configurations.

''What would you guys say?''

relative mass relative charge
proton...........1..............+1
neutron.........1.............. 0
electron.....1/1836..........-1

The proton and the neutron don't have [exactly] the same spin. They have nearly the same spin, and because of this, Heisenberg developed isospin theory. Of course, the neutron is neutral whilst the proton has a positive charge. The proton has a mass of 938 MeV whilst the neutron is just slightly higher as 940 MeV. The electron has a negative charge -1, and has a mass of something like 0.510990615 MeV.

The protons and neutrons make up the nucleus of the atom - the heart of all atoms. 99% of the whole mass of the atom is contained within the nucleus. The shell is very lightweight, and is 10,000 times larger than the neutron. The shell itself has no charge. The electron is attracted to the nucleus because they contain a negative charge... Because the charge of the atom and the neutrons are neutral, the electrons are attracted to the positive charge of the proton.

You can work out the numbers of nucleons (that is protons and neutrons).

Number of protons = ''atomic number'' of the atom - it is also called the proton number.
No of protons + no of neutrons = ''mass number'' of the atom.

In this hypothetical atom, let's call it X, what is the atomic number> How many protons and neutrons are there?

19
X
10

To work this out is not difficult. The lowest number at the bottom is 10, which is the proton number - thus, the 19 above calculated the mass number, so 10-19=9 neutrons.

You can also work out the number of electrons inside an atom. The rule to calculate electrons is simple. The number of electrons = the number of protons. This is because the entire charge of the protons must be renormalized by the charge of a negative force (electrons).
Electrons are found to orbit the nucleus, much like the earth orbits the sun. They are also found to be quite a considerable amount of distance away from the nucleus, in rings called ''energy levels.'' Whenever we talk about the electron, we very rarely talk about it as being a particle as such, but rather we speak of its cloud, because that is all the electron was... just a cloud of probability due to the wave function.
The most electrons that can be contained on a level is 8. The first level, the inner-most ring will contain 2 electrons. The second and third level contains 8 electrons. After the third level, we move into sublevels... clouds within clouds.

So as you can see... my answers would be too obtuse for your work.

Yo keep in mind im a 9th grade average student who hasnt been exposed to chemistry. Im in biology but were doing chemistry. I understood mostly what reiku said and ty but I need an explanation of what an electron cloud exactly is and how to explain it. I mainly need help with passingtimes analogy cause i think it would help alot in my explanation if I knew what I was talking about.

The electron cloud [is a cloud] because of something called ''the quantum wave function.''

I'll simplify.

Take a single electron inside an atom. The electron cannot have a defined position and a path (orbit) simultaneosly because of a complex principle called ''uncertainty.''
Whenever one attempts to locate an electron inside an atom, its position is disrupted, and its paths becomes infinite.
It is able to have an infinite amount of paths because of the wave function, which is a measure of all possbilities, or probablities. So, an electron can be in more than one place at one time, and this is what make up a ''cloud of possibilities.''

I hope this helps...

So are you saying that an electron is in more than one place at one time forming a cloud? If what you were saying was the answer than ok, but ive heard so many contradicting statements today, I dont know what to believe. Also, whats this have to do with the apartment thing, I really need to know because this would help prolong my speech time giving me an A.

"In the electron cloud analogy, the probability density of an electron, is described as a small cloud around the atomic or molecular nucleus or in free space, with the thickness of the cloud proportional to the probability density."

What's that mean?

''"In the electron cloud analogy, the probability density of an electron, is described as a small cloud around the atomic or molecular nucleus or in free space, with the thickness of the cloud proportional to the probability density."

Right, this might be too complicated for you. Instead, i'll rephrase something similar i know you will understand:

The probability of charge, angular momentum, density and positions are located in the configuration of the cloud, which is nothing more than a cloud of possibilities. This cloud determines the [likelyhood] of finding the electron at any given space within the atom.

The electron cannot move near the nucleus, because it would violate certain principles, [namely] the uncertainty principle i mentioned above. Therefore, we say the electron exists around the nucleus in such a cloud.

The apartment was actually a good description i've found for the nucleus, but not so much for when we are speaking about clouds... (I'm not sure why they have mentioned this... i'll need to look back)... But instead, Dr. Jim recently in a T.V. program called 'the Atom' used an apartment to explain quantum jumps...

In an atom, we have levels, as you have been taught so far. These levels are much like the levels we would find in an apartment, but quantum physics says that no two electrons can ever be in the same level*...

''So are you saying that an electron is in more than one place at one time forming a cloud? ''

It would be worthy to note that whilst the particle is in such a state, its not really real, but in a state of something we call, ''superpositioning...'' This is when an electron for instance can move through spacetime, and have more than one outcome for its position and path... so in a sense, one can say that the electron is in more than one places at any given time, that is, until a collapse is made in the wave function (that same function that gives all subatomic particles this ghostly cloud of possibilities). A collapse can happen by a number of ways, such as decoherence, or by observing the little particle through a telescope, or even placing the electron in a strong magnetic field.

* I starred this off, because i didn't want to make this too complicated... but, two electrons cannot be on the same level because of something called the exclusion principle, and they exclude by having different spins (x,y=1/2 and x,y=-1/2) or a different energy.

Edit> If you have any more questions, feel free to ask... and you have my permission to use any work i have thus presented.

Ok ty I'm starting to get a better grasp on the whole concept, however back to the apartment thing, you said electrons cant be on the same level. Were u referring to the electrons in the spdf thing? You said before that it was used to describe the nucleus, but I thought electrons cant be in the nucleus. And if there in the outside, arnt there only 4 levels they can be in? Its my understanding that each orbital shape takes on an energy level from 1-7 but there can be up to 14 electrons in the cloud. Please clarify. Also, how can an electron have a position if its always in an orbit

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The apartment is part of the nucleus in this diagram... since the bottom floor... (the ground state) is where the protons and neutrons are, so the electrons cannot fall to the bottom state.
The most electrons that can be contained on a level is 8. The first level, the inner-most ring will contain 2 electrons. The second and third level contains 8 electrons. After the third level, we move into sublevels... clouds within clouds. The discovery of clouds within clouds is a result of quantizing the atom.

... please.. listen carefully to these words...

The electron can be on the same level in the atom, but they must cancel each other out...
The diagram is poor if you want to be scientifically accurate, because truth be known, you can have as i have shown you, 8 electrons is the highest found in a level... and there are four levels, one, two and three... the forth level is troublesome, but equally important.
The levels in the apartment, at least from my perspective, was to show you that electrons inside the atom are unique... unique that the other electrons cannot fall into the same quantum states.

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*When is say ''fall into the same quantum states,'' i mean two electrons falling into the same levels with the same spins (a spin up)... or (a spin down.)

Gracias Senor. I will include this all in my speech tomorrow and hope for the best. Thank you for your time, my understanding is much better now and although I can't grasp the concept completely I will be able to sound almost as smart as you and hopefully I will get an A. Thanks again.

Don't leave an iota out. One tiny mistake, and it won't make sense.

Best luck my friend.