Electrons are found in orbitals outside the nucleus of an atom.
Electrons exist as pairs. Although, electrons hate each other, and only go as pairs as a last resort.
In the nucleus
Free electrons exist in the conduction band, which is the highest energy band in a material where electrons are free to move and conduct electricity.
it doesn't exist
No
valence electrons
Between electrons and the atomic nucleus a repulsion exist.
The symbol An doesn't exist.
The maximum number of electrons that can exist in 4f orbitals is 14.-pg. 110 Modern Chemistry table 2:)
These electrons are called "excited".
Electrons have dual properties.
When a material has an excess of electrons, it has a negative charge. When it has a deficiency of electrons, it has a positive charge.