i have no idea when it was discovered
Electrons are the particles found in electron clouds.
in the energy levels. energy levels are in the electron cloud.
electrons are found in electron clouds.
the orbitals
electron cloud
The place were the electrons are found
Electrons are found in the electron cloud (or orbitals) around the nucleus of an atom
Electrons are found in the electron cloud that surrounds the nucleus.
Electrons are found outside the nucleus in the electron cloud.
This question doesn't technically have an answer. The electron cloud simply surrounds the nucleus and contains the electrons. Each atom of different elements has a different number of protons. It is not determined by the electron cloud. An electron cloud doesn't have a nucleus as the question implies either. An electron cloud odes not contain protons either. Just electrons, as the name suggests.
I think the word you're looking for is "electron cloud". That term already describes where electrons are found. It would be kind of silly to define "electron cloud" in such a way that it describes an area where electrons are not found, wouldn't it?
The space around the nucleus of an atom is called the electron cloud. The electron cloud is the space in which the electrons of that atom travel. Compared to the nucleus, the electron cloud is enormous.