why should the atoms degenerate orbitals orient differently in difeerent directions under external fields?
148700
Typically this refers to magetic fields.  If you align a large magnet (like a NMR - nuclear magnetic resonance instrument) protons or electrons (ESR - electron spin resonance) are aligned to a certain angle and the like.  Once the magnet is removed, the electrons and protons can start "precessing" and this is recorded via the sound it emits and it is then Fourier transformed into a typical spectra that can be interpreted. \n\nAtoms in degenerate orbitals will align under a big enough magnetic field.
570126
It all comes down to two forces: the attraction between electrons and the nucleaus and the repulsion between the individual electrons.  This leads to a complex set of equations that do not have a solution. \n\nIf we assume that molecules behave as a combination of atomic states of only one electron, then we can try to formulate solutions of the equations (because the electron-electron repulsion term is zero). \n\nUnfortunately, the equations do not have a single answer. They have multiple answers. These answers have been called electronic configurations and are your different shells, sub-shells, etc. The actual quantum numbers are seen in the equations as solutions to the Schroedinger equation(HY=EY): n, l, ml, and ms.\n\nThe prevailing intepretation are that these states are energy levels which can be occupied by electrons as the form molecular bonds. \n\nMy university professor would probably remove my liver for such a poor description of the phenomenon, but this was always my best understanding of it.
261105
Better than what?\n\n\nHere's a description of the result:\n\nEach successive "shell" has the capacity to store one more group of paired electrons in a new kind of orbital.\n\nPrincipal quantum number 1:\n1 s-orbital\n- will hold one pair.\n\nPrincipal quantum number 2: \n1 s-orbital\n- will hold one pair.\n3 p-orbitals\n- will hold 3 pairs.\n\nPrincipal quantum number 3: \n1 s-orbital\n- will hold one pair.\n3 p-orbitals\n- will hold 3 pairs.\n5 d-orbitals\n- can hold 5 pairs, but due to "crowding" wait until the 4th S orbital is filled. Are available to help form double bonds for elements like P, S and Cl though.\n\nFor principal quantum number 4 there is the addition of 7 f-orbitals, which insert themselves after the first d-orbital of the next higher principal quantum number is filled.\n\nAs a result, there are lots of rare metals which form 3+ ions...\n\n\nNow why is this so?\n\nThere is no easy way to explain this with classical mechanic and electrostatic. It has to do with standing waves, elimination by interference, and the wave/matter duality. In short, quantum mechanics. If you don't want to start with that topic, just accept that this is how it works...
815589
it is very simple, the shells, subshells actually represent energy levels in the atoms. it is just like big building having different storeys and them again the rooms. You can compare storeys as shells, and individual apartments as subshells and the rooms in each apartment as orbitals where we the electrons are revolving
134534
Microwave energy levels usually manifest as molecular rotations, not vibrations along the bond. However, in a densely packed liquid the attempt to rotate is translated into  a vibration of the superstructure.\n\nThe basic widened tetrahedron angle of water doesn't alter significantly (or more importantly, permanently). It is only a mean angle anyway, since the molecule is a vibrating system.
731498
The orbitals themselves have no real "shape".  The graphical representations you are looking at are actually density maps of where an electron in that orbital is most likely to be found.\n\nIf you take a look at an "f" orbital, for example, you'll see that the "shape" is not contiguous.  It looks like a hourglass going through a donut.  Electrons being the happy things they are can appear the various different permitted energy levels around a nucleus and can even "tunnel" outside the atom itself.  Just remember when you're looking at those pictures that you're not really looking at shapes but density graphs of where an electron in that type of orbital can most probably be found.
126760
In general, polarization represents a bias or preference - whether it's a polarized molecule (like H2O), the polarization state of an electron, or a polarized radiation field (such as light or microwaves).  In all cases, to polarize means to impart a bias to a particular, preferred state.  \n\nThe molecule "prefers" to be polar - which in that case implies a seperation of charge - because of the arrangement of the valence electrons in hydrogen and oxygen, so it is biased toward a tetrahedral geometry, which it assumes as a consequence of it's polarization.  \n\nThe electron "prefers" certain electronic states and values of spin, or orbital angular momentum, as a result of it's location in the configuration of the atom, so it is biased to be polarized with "spin up" or "spin down" - according to the Pauli Principle.  \n\nThe radiation field is composed of transverse electromagnetic waves which can be polarized in the sense that they "prefer" to interact with a material that the field encounters, or to not interact with the material that it encounters.  This all depends on the direction of oscillation of the electric field vector component of the wave field.  However the electric field vector is pointing (oscillating), well, that's the plane of polarization.  Fields may also be elliptically, circularly, or randomly polarized in the case of a changing direction of the electric field vector over time.\n\nOne could just as easily imagine that if light can be polarized to bias interacting with a material, then so could any electromagnetic radiation field, for example a microwave field or an x-ray field.\n\nIn any event, the polarization is a bias toward a certain state or configuration.
745353
the answer is probably b (I will get to the "probably" part later). the path the electron takes would be bent by the magnetic component of the field (producing a curve) and it will be pushed by the electric field changing the direction toward a specific direction (along the electric field), but movement will all take place in a plane which is along the original direction of propogation IF the electric and magnetic fields are at 90 degress to the original projection. \n\nFor different orientations of the fields, it is also possible to get helixes for the movement path, which do not apply to any of the answers.\n\nAlso, for specific initial velocities, electric and magnetic fields, it is  possible to obtain a straight path.\n\nIf the electromagnetic field is varying with time, there cannot be an answer to this question, since the path can be totally erratic.
951079
b and d are not right.\n\nb. - going across a row the atoms get smaller so Co is smaller than Fe\nd  - Na is in row 3 and is larger than Be and Ne which are in row 2
852794
dobereiner's like that mendeleev guy right? if my memory is right, all  of the elements above have similar chemical properties, that's why he placed them in his "triads". This means that all of them act similarly. Remember that it is the VALENCE electrons that causes the specific reaction of an element. So, as all three elemnts have the same number of valence electrons, they act similarly.
1105737
even though it would seem that 3d orbital is lower in energy it is actually higher in energy.  That is why the 4s is filled first.
446643
The movement of an electron from one place to another.
509181
H2 because it will be electronically more like Helium. It will have an electron with 1/2 spin up and 1/2 spin down. It will therefore have a happy orbital. You can also say that the bonding orbitals are occupied, and the antibonding orbitals aren't.
86731
The splitting and shift of a spectral line into several components in the presence of an electric field.
947336
D - it's a symmetrical molecule, so even though the individual bonds are polar bonds, the molecule itself has no net dipole
549677
This is a chemistry question, the anomaly is due to Hydrogen bonding.
115249
Try this URL... it shows some diagrams.  Although it does not have the full set of configurations for d and f orbitals.