About neutrons and proton in nucleus

[shivakumar06]

sir i want to know why is number of neutron is more or equal number of proton in nucleus of atoms whose atomic number is more tnan one?

 

[Drakkith]

Neutrons help provide more strong force to hold the nucleus together without adding repulsive EM force. I would guess that more neutrons are required than protons because the range of the strong force is very short, less than the radius of the nucleus in higher atomic number elements, but I'm not certain.