In ambient air, such energetic electrons typically come from cosmic rays.

The question I had was where did the electrons come from in the wires to provide electrical power to the grid.

So the electrons being pushed out one side of a piece of wire are coming back in the other side.

These electrons can come from lone pairs, pi or sigma donors.

When the electrons come with half the period, they interfere destructively.

The same is true if the electrons come as a bead chain.

You need to supply energy (apply a voltage) to get electrons to come out of the box.

The first electrons to be ionized come not from the 3d-orbital, as one would expect if it were "higher in energy", but from the 4s-orbital.

The atoms that the electrons came from just end up with an overall positive charge.

The top layer exposure is effectively less because electrons emitted from the surface never come back.