Do electron shells actually exist?

First of all, strictly speaking, electron shells (as well as atomic orbitals) do not exist in atoms with more than one electron.

Who proposed the idea that particles could as well behave like waves?

Louis de Broglie
French physicist Louis de Broglie proposed (1924) that electrons and other discrete bits of matter, which until then had been conceived only as material particles, also have wave properties such as wavelength and frequency.

How do the principles of quantum theory describe electrons?

Erwin Schrödinger proposed the quantum mechanical model of the atom, which treats electrons as matter waves. Electrons have an intrinsic property called spin, and an electron can have one of two possible spin values: spin-up or spin-down. Any two electrons occupying the same orbital must have opposite spins.

How were electron shells discovered?

In 1913 Bohr proposed his quantized shell model of the atom (see Bohr atomic model) to explain how electrons can have stable orbits around the nucleus. To remedy the stability problem, Bohr modified the Rutherford model by requiring that the electrons move in orbits of fixed size and energy.

How does an electron act like a wave?

When electrons pass through a double slit and strike a screen behind the slits, an interference pattern of bright and dark bands is formed on the screen. This proves that electrons act like waves, at least while they are propagating (traveling) through the slits and to the screen.

How an electron can act both like a particle and a wave?

Electron and atom diffraction Experiments proved atomic particles act just like waves. The energy of the electron is deposited at a point, just as if it was a particle. So while the electron propagates through space like a wave, it interacts at a point like a particle. This is known as wave-particle duality.

How does quantum mechanics explain the atomic energy spectra?

It took a full understanding of Quantum Mechanics to explain the atomic energy spectra. Compton Scattering:When light was scattered off electrons, it behaved just like a particle but changes wave length in the scattering; more evidence for the particle nature of light and Plank’s postulate.

Do electron shells exist in atoms with more than one electron?

First of all, strictly speaking, electron shells (as well as atomic orbitals) do not exist in atoms with more than one electron.

What problems with classical physics led to the development of quantum mechanics?

The problems with classical physics led to the development of Quantum Mechanics and Special Relativity. Some of the problems leading to the development of Quantum Mechanics are listed here. Black Body Radiation:Classical physics predicted that hot objects would instantly radiate away all their heat into electromagnetic waves.

Why are electron energies quantised?

This is basically why electron energies in an atom are quantised. You’ve probably heard that electrons behave as waves as well as particles. Well if you’re trying to cram an electron into a confined space you’ll only be able to do so if the electron wavelength fits neatly into the space.