Just use a Magnifying Lens and count them by hand !!!!!!!!!!!!!!!!!!!!
I would actually like to try that out.
Anyways, using a periodic table, the atomic number is the amount of protons and electrons in the atom. Hope this helped!
The number of electrons in an atom is equal to the number of protons (Atomic number of an element)
Well for example take calcium, its atomic number is 20 (Electrons=protons)
we have 4 orbits (For begineers)
which are called k l m n
But forget about this for now,
in the first orbit the maximum number of electrons placed is 2
in the second orbit it can take up to eight as well as the third and the fourth so it would be:
2 8 8 2
(Ran out of electrons to fill the 4th orbit(N)) When this atom gets in chemical reaction, it will lose 2 electrons and have a +2 above it so it has an outermost level shell (Valency electrons) = 8