Re: How does an electron look like when it is observed through a microscope?

The term "electron cloud" is a bit misleading. It is known that it is not
possible to determine the position of electrons in atoms and molecules. It
is only possible to say that there is a certain "probability" of finding an
electron at a given position. If you think of "taking pictures" of the atom
or molecule -- lots of them -- you would find the location of the electrons
more likely to be in some places than others, but not exactly in the same
places. So the collection of the snap shots will be "cloudy". Hence the 
term
"electron cloud."

A "cloud" of something means a lot of them close together but not
constantly touching each other, usually in the air.  You can talk about
a rain cloud -- a bunch of water droplets in the air, or a cloud of
flies or gnats.  Scientists use "cloud of electrons" to describe a loose
collection of electrons.  Generally, a cloud of electrons only occurs in
small chambers in laboratories where scientists study how they react
with other things.