The number of protons in an element does not vary, an element may have differing numbers of neutrons. Electrons are negatively charged. Each atom will have as many electrons as protons and thus will be neutral. Electrons occur around the nucleus - current theory describes the likelihood of an atom being in a given position. For convenience, we depict electron position in circular shells but they are not restricted to a fixed orbital location or path.
Atoms have a name, an abbreviation, and an atomic number.
Hydrogen is 1, carbon is 6, lead is 82. The atomic mass is the sum of the masses of all the protons and neutrons. By convention each proton and neutron have an atomic mass of 1. The periodic table is an organizational structure for elements. There are 92 naturally occurring elements.