Can someone help me with drawing valence electron shell diagrams?
Well, I'll try to answer it pretty easy. I just learned it a few weeks ago so it's pretty fresh! Ok first you have to know how many valence electrons are in whatever atom you are trying to draw. The easiest way to figure this out is to look at the top of a periodic chart and use the numbers with A after. For example, element 11 (sodium) is in group IA so it has 1 valence electron. Element 34 (selenium) is in group 6A and has 6 valence electrons. This way only works for atoms in the Representativee elements but those are a good place to start to learn how to do the rest. After you find the number of valence electrons, all you have to do is right the electron shell diagrams, also know as lewis structures. All you have to do to draw these are know how many electrons total or electron in the valence, whichever you are asked to write. The first electron orbital can only hold 2, but the other shells after that can hold a maximum of 8 electrons. To put this all together, you take the element + the number of electrons: Carbon (C=element 6 in group 4A) Right there you know that Carbon has for valence so you can either draw that right off the bat OR you and draw C with two dots in the first orbital and 4 dots in the second orbital. I hope that helped!! If you need more help or examples, try going to chemtutor.com. That site always seems to help me.
The photoelectric effect is the conversion of photons to current. To do this an electron must be allowed to absorb said photon, thereby increasing its energy, allowing said electron to dislodge itself from whatever bounded atomic or valence state it is in and start to “flow”, or cause a cascading virtual flow of electron holes.If the incoming photon is too energetic the electrons ignore it. Why? Right! Because they are not allowed to absorb the energy according to the immutable laws of quantum.Now atoms with higher atomic number have outer electrons which are more energetic when the atom is in ground state than their smaller lighter atomic brethren. Why ? Right again! Because the lower energy states allowed for in its inner shells are already filled with sibling electrons.Since the electrons in the outer shell of a heavier (higher atomic number) atom have more energy they have gravitas, so to speak, in the quantum court, to legally absorb a big energy photon in exchange for being liberated from said atom.Game over, cheers!
Can someone help me understand the physics of quantum theory in regards to basic atomic structure?
The best basic explanation I've heard of quantum mechanics was a recording of a Feynman lecture from 1962 titled "Quantum Behavior." You should find that and listen to it, he breaks it down real good. Quantum mechanics is just a description of the behavior of very small things. It's necessary to have such a description because very small things act very oddly. Specifically, things like electrons and photons can be shown in some experiments to behave like waves, wheras in other experiments it can be shown that they behave like particles. So which are they? Quantum mechanics reconciles this. It says that quantum particles act like waves, as long as you're not "looking at them." That is, they act as if they were in a lot of places all at once, in wavelike patterns, interfering with each other and so on. But if you "look at them," you will find them to be in some specific location, as a particle. and all the wave like phenomena will disappear. This happens because, in order to "look at them," you have to bounce some other quantum particle off of them. You can't "see" where an electron is, unless you bounce a photon off it for example. Or in other words, you can't observe quantum particles without changing their behavior. The upshot of all this is, that it's impossible to know the complete situation with any given quantum particle. You can see where it is, but then you can't see the effects of its normal, wavelike behavior. Or you can see the wave effects, but then you don't see where the particle is. You can never see both at the same time. This means there's a fundamental limit to how exactly we can describe a given situation. An old saw with logical positivism used to have it that, if you knew the exact position and velocity of every particle in a system, you could predict its future states, all the way out to eternity. That is, if you knew enough about reality, you could predict the future with perfect accuracy. Quantum mechanics say that can never happen.
Periodic Table/Electron Bonding Help 10 Pts :)?
Rows go across and columns go down. Electrons occupy shells (or clouds). The first shell can have up to 2 electrons and the second shell can have up to 8 electrons. There are more shells but in inorganic and organic chemistry you are typically only concerned with the first two. Elements try to fill the outer most shells to be stable. As you can see on the periodic table, each column is numbered I, II (a & b), III, IV, V, VI, VIII,VIII. The elements in the I column have 1 electron in its outer most shell (has one electron available for bonding, i.e. H), elements in the II column have 2 electrons in its outer most shell (2 electrons available for bonding i.e Be), elements in the III column have 3 electrons in its outer most shell (3 electrons available i.e. B), and so on up to the final VIII column. The halogens, or elements in the last column, VIII, have 8 electrons in its outer most shell and typically only bond in halogen bonding which you probably don't need to know at this point...but hope the rest helps! Your table should look like this: http://library.thinkquest.org/12909/main2.html
To be able to find someone who can understand us is hard for these reasons:First we need to understand ourselves and be ourselves, always be honest and only do things that represent ourselves. (Ex: if your friend brings you to an icecream shop feel free to tell her you don't like icecream even if it can be considered rude and abnormal). We need to show the world who we are so that those people like us out there can find their way to us.Sometimes we are stuck with the idea about what the person we like has to be like and to understand someone takes time. Sometimes we have to start with being friends first.Also, try someone who has good buddies and or has a sister (if you're a girl), this gives them experience in listening and sharing well.And at last the people who can understand us sometimes aren't interested in us romantically. I have met someone who is capable of understanding me but it's useless because he was never interested in me. If you want someone who understands you to be with you, maybe you will have to understand them first.Most people would want to spend their life with someone who can understand them I'm sure. There's no point spending hours just to explain 1 simple thing.
EnthalpyEnthalpy can be explained by Joule Thomson expansion(Throttling Process). It is somewhat different from free expansion. Joule Thomson expansion will occur under controlling pressure atmosphere whereas it is not in the case of free expansion. Let us consider the given Diagram.Two adiabatic pistons are enclosed by adiabatic walls and the pistons are separated by a porous plug (horizontal lines) which allows the mass to transfer. A constant higher pressure Pi is maintained on the left hand side of the porous plug and a constant lower pressure Pf is maintained on the right hand side. Now, the mass will transfer from left to right. Since this process is adiabatic one Q=0 in the relation (first law of thermodynamics)Uf – Ui = W+QUf and Ui are final and initial internal energies and W is the work doneSince this process occurs under controlled pressure the net work done will be – (PfVf-PiVi) where P is the pressure and V is the Volume.Now, Uf-Ui = -(PfVf-PiVi)Uf+PfVf=Ui+PiViHf=HiWhere,H is enthalpy. Thus for throttling process the enthalpy of final and initial states are same. From this we can have the general relationship for the enthalpy as H=U+PV.EntropyEntropy is a measure of disorder. It always indicates the direction of process. In an irreversible process, entropy always increases. The best example is sublimation process. The solid is in a state of order. As latent heat supplied to solid, it becomes vapour which is in the highly disorder state under constant Temperature. Thus the increase in entropy of a system can be described as an increase in the disorder of the system by the equation Sf-Si = dQ/T.The concept of entropy is important in the discussion of time. In all ageing process, entropy always increases. For instance, green apple to overripe apple, structure to erosion e…. One precedes another. Order precedes disorder. So, in a metaphorical sense, Entropy is the arrow of Time.Reference : Heat and Thermodynamics, Zemansky, Dittman
Please Help!!! How do I draw electron shell diagrams?
Ok Step 1: Look on the periodic table. This tells you lots of things. The order (Starting a hydrogen) tells you how many protons are in an atom. If you are drawing an atom, the number of protons = the number of electrons. Next: There is a specific way that electrons are arranged, which we call shells. In the first (and closest to the nucleus) only a maximum of 2 electrons can fit there. If you were to draw hydrogen, you would put 1 proton in the nucleus and 1 electron in the first shell and with helium 2 protons and 2 electrons in the first shell. After 2 electrons , the 3rd electron goes into the 2nd shell out from the nucleus. eg lithium has 3 protons in the nucleus, 2 electrons in the 1st shell and 1 in the 2nd shell (total of 3 electrons). There can be up to 8 electrons in the 2ns shell eg. Neon has 10 protons and 10 electrons, 2 in the first shell and 8 in the 2nd. After this you have to go into a 3rd shell which again takes up to 8 electrons. The 4th shell (in your case will probalby only have 2 electrons in it) can take 18 electrons Potassium has 20 protons and the electrons are 2 (1st shell), 8 (2nd shell), 8 (3rd shell) and 2 (outer or valence shell). or 2,8,8,2. All you have to do is know how many electrons can fit in each shell (eg 2,8,8) and you can figure out the shell diagram. Other examples: Carbon 6 protons and electron arragment is 2,4 Fluorine 9 protons. electrons are 2,7 Magnesium 13 protons, electrons are 2,8,3 Hope that makes sense (its hard when you can't draw it).
Aluminum Hydroxide.Aluminum hydroxide is a binary ionic compound, which is comprised of a metal cation (positive charge) and a polyatomic anion (negative charge). In this case the cation is Aluminum and the anion is Hydroxide.Aluminum always has a charge of +3 (I'm not entirely sure why). Hydroxide, on the other hand, has a charge of -1. So, to explain the parentheses.The parentheses are used to show that Hydroxide is Hydroxide and not just an oxygen and a hydrogen in a non ionic compound. You are correct about there being 3 Hydrogens and 3 Oxygens, because a subscript after a parentheses indicates that it is applied to the whole inside of the parentheses. But we don't look at it as 3 Hydrogens and 3 Oxygens, rather as 3 Hydroxide ions. When calculating molar mass, however, you do calculate it as having 1 Aluminum, 3 Hydrogens, and 3 Oxygens. And the reason why it's 3 Hydroxide ions insteas of 2 or 1 is because Hydroxide's charge of -1 needs to cancel out Aluminum's charge of +3, so there need to be 3 Hydroxides to make that happen(3-1-1-1=0).