The band of stability curves upward at higher atomic numbers, why?

• A. Since neutrons have no charge, excess protons are required to keep the nucleus of an atom from falling apart.
• B. To keep a higher number of electrons stable in their orbits around the nucleus, a higher nuclear mass is required.
• C. As the atomic number increases, nuclear repulsions increase. Therefore, excess neutrons are required to reduce intranuclear repulsions.
• D. Excess neutrons are required so that they could be converted to protons in needed.

Answer: (C)