What is the maximum number of electrons in an atom that could have the quantum numbers of n = 4, l = 0 ?

The correct answer is "atomic weight".

Carbon based or cells?

The atomic nucleus made up from protons (yellow) and neutrons (blue) and held together by nuclear forces. nuclear forces (also known as nuclear interactions or strong forces) are the forces that act between two or more nucleons. they bind protons and neutrons (“nucleons”) into atomic