Therefore, rows show levels and column in major elements show number of last level Electrons. As an example, Si has 3 levels (2,8,4) and 4 Electrons at last level.
Then, at column number 18 maximum number of Electrons at last level could be 8. Elements less than 4 Electrons on last level are conductors like metals and more than 4 are insulator. Then, elements by 4 Electrons at last level should be Semiconductor.
Now, there is a question. If Electrons in an Atom located specifically, is manipulation possible?
The answer is positive but there should be external Energy source like heat, light or others. Then, last level Electrons can get energy and make more distance from nucleolus.
Second question. Can we achieve Energy by manipulation like a power plant?
The answer is positive what expected in solar cells. When Electrons are stimulated by an external source of energy as light, heat or misc. Electrons go further but when source remove, refer to Energy Conservation Law (Energy is fixed in the world. In words, it is not created or it is not destroyed. Only it can convert to the types of Energy as Electricity, Magnetism, Heat …) Electrons pay back all Energy they achieved and go back to initial level.
In short, Electrons agitation by light source, change its position and when it comes back pay back all Energy achieved. Remember steam power plant that fuel (Chemical Energy) burns and make super heat vapor then vapor runs Turbine and Turbine turns Generator what produce Electricity.
If there is a closed loop system, Electricity generating by Photovoltaic cell according to the above principles is possible. Light Photons agitate Electrons and they will turn in the circuit.
Now, deeper investigation shows how it works. First N type and P type of semiconductor is important. Basically, there in nature there should be different potential and then Energy transferring possibility. This is same as water on a Ball on a sloped surface.
When N and P type semiconductors connect make Depletion region and it is expected whole negative and positive charges neutralize each other. If it was correct, it would be no chance to make a closed loop and then Energy generator because they would be in short circuit.
Fortunately, nature is perfect. Negative and positive charges attract each other on depletion zone but not whole of the charges have the possibility. Then, some negative and positive charges neutralize each other on depletion zone and make a barrier that does not permit rest of charges neutralize each other.
Photovoltaic under sun irradiance agitates negative and positive Charges that coupled and neutralized in depletion region and push each of them back to their initial region and if sun irradiance (external Energy source) remove, they will come back to each other in depletion zone. But there a lots of sun irradiance Energy and we can use.
Agitated charges wait to find a way back to neutral condition and then there is a potential. Now closed loop time. If semiconductors connect from the other sides, there will be a chance to neutralize each them and provide us Electricity.
When a couple of charge is agitated by sun irradiance and push back to their initial region and then flow through the circuit (closed loop) the other charges in N and P semiconductors find each other on depletion zone and scenario will be repeated.