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hetanshu
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why do electrons revolve around the nucleus?
hetanshu said:so are they stationary?
Not true in general. You can see this by calculating the expectation value of the momentum of the electron from its wavefunction, and finding that the momentum is in general nonzero.akashpandey said:Electrons are stationary wave
They are not noving
akashpandey said:Electrons are stationary wave
They are not noving
Thank you for the clarification.jfizzix said:The expectation value of the momentum [itex]\langle p \rangle[/itex] of an electron in a single orbital [itex](n, \ell, m_{\ell})[/itex] is indeed zero. This can be seen from Ehrenfest's theorem, and that the expectation value of the position is a constant for one of these eigenstates.
However, the variance of the momentum [itex]\sigma_{p}^{2}[/itex] is nonzero even in these states, which means that you are very likely to find the electron having a nonzero momentum if you actually measure it (it's only zero "on average").
Also, most electrons (I would think) exist in a superposition of different orbitals (i.e., their wavefunctions are not stationary, even if they are still concentrated around the nucleus). In this case, the expectation value of the momentum may change in time all sorts of ways.
i will checkTeethWhitener said:Not true in general. You can see this by calculating the expectation value of the momentum of the electron from its wavefunction, and finding that the momentum is in general nonzero.
This may be nitpicking, but even in eigenstates [itex]\langle p \rangle[/itex] is only zero in one inertial frame---the one in which the nuclear core to which the electron belongs is at rest. If the entire atom is moving (core and all), the electrons have non-zero expectation values of momentum, too.jfizzix said:The expectation value of the momentum [itex]\langle p \rangle[/itex] of an electron in a single orbital [itex](n, \ell, m_{\ell})[/itex] is indeed zero. This can be seen from Ehrenfest's theorem, and that the expectation value of the position is a constant for one of these eigenstates.
Electrons and protons are subatomic particles that make up the atoms of all elements. Electrons have a negative charge, while protons have a positive charge. They are essential to the structure and behavior of atoms.
Electrons and protons revolve around the nucleus due to the electromagnetic force. This force is attractive between positive and negative charges, causing the negatively charged electrons to be attracted to the positively charged protons in the nucleus.
The electrons and protons stay in orbit around the nucleus due to the balance between the attractive electromagnetic force and the centrifugal force. The centrifugal force is the force that makes objects move in a curved path, in this case, around the nucleus.
The number of electrons and protons in an atom is determined by its atomic number. The atomic number is the number of protons in an atom, which also determines the number of electrons since atoms are electrically neutral.
Yes, electrons and protons can exist outside the atom. When atoms are ionized, meaning they have gained or lost electrons, the electrons and protons can exist independently. However, their natural state is to be in orbit around the nucleus.