Types of problems are generated by resource extraction and usage?

If element x has 99 protons how many electrons does it have

Three resistors are connected in series across a 15-v power supply. if the potential drops across resistors 1 and 2 are 4.1 volts and 3.1 volts, what is the exact potential drop (in volts) across resistor 3?

Which substance partical has negligible massand travels around outsidethe nucleus