How does an electron move from one part of its orbital to the other!?
Hello, This is a trick question. In the pure Atomic P "orbital" (which gives the probability of finding an electron in space), the electron never "moves" from the red (assume this is the "negative" wave function) to the blue (assume it's the "positive" wave function) via crossing the node (area of zero electron density/zero probability of finding an electron) because, the electron is at both places at once due to its wave-like behavior, UNLESS we try to measure its position in space. If we do, we'll discover that the electron will be in only ONE of the two lobes of the P orbital; "red" or "blue", and not in both or directly between the two lobes (the "node"). Thus, the act of "looking" at the electron with photons causes the electron to stop behaving as a wave and begin behaving as a particle due to light waves interfering with electron waves. If multiple measurements of the electron's position were made over time with exposure to photons, we would see that the electron would be at the middle section of the red lobe in one measurement (higher probability), more towards the end of the red lobe in a second measurement (lower probability), in the blue lobe the third, etc, until we get a collection of positional points that creates a P orbital shape. This is how the electron would look if no photons were present to "observe"/interfere with it. The reason that there's a "node" is because the electron is behaving specifically as a "standing" sinusoidal-like wave when it's not being observed. For a visual demonstration that supports he electron's wave-particle duality nature, please view this video: http://www.youtube.com/watch?v=DfPeprQ7o... **Thus, electron's don't "move across nodes" within their own orbitals because, the shape of that orbital (probability region) they reside in is, in a sense, the electron itself. However, electrons can move from the orbital it's within to a different orbital via excitation by light or heat, followed by a decay/movement back down to it's original/more stable/lower energy orbital (while releasing photons/light proportional to the energy gap between the two orbitals the electron moved between).
When an electron jumps from a lower energy level to a higher energy level (as we know that it absorbs energy), where is this energy coming from?
The energy comes from a photon. Is there any other way the electron can get that energy? I believe the answer is no, "by definition".In a simple case like photoelectric effect, the photon comes from light shining on the atom. However the electron can also be hit by some other incident stray particle. That can "kick it" up to another energy level. Any such energy exchange in QED is mediated by a photon. When a particle "hits" another it's called "interaction” (via EM force, in this case) and "scattering". Each particle emits "virtual photons". When one of those is absorbed by the other it "becomes a real photon". The mathematics is precise but the description is not.The original source of the energy may have been heat, EM potential, even a violent shaking (kinetic energy). Regardless, when it's actually absorbed by the electron, it's always thought of as, or represented by, a photon.Physics is vague. We don't really know why or how anything happens. Don't forget, a photon itself has only a shadowy existence. You can imagine there's no such thing, it's just a way of talking about exchange of energy at the subatomic level. This is like the question "what causes length contraction?" or "what causes wave function collapse?" Physics can't, or at least doesn’t, answer such questions. The math tells you what happens. We have an "intuitive picture" of what's going on, but that's all it is.Bottom line: energy level transitions always either absorb or emit a photon. But that's not really as informative as it appears.
The reason why electrons can only orbit at certain circumference is?
I would have to say c on this one, because if the electron radiates energy, then it goes down to a lower energy level, and hence a smaller orbit circumference. I'm certain a,b, and d are all wrong for this question. I don't know what de Broglie wavelengths are, however; I say the answer is c, with about 85% certainty.