Hi there First of all excuse my English. My question is: Why a nucleus with more neutrons than these in the valley of nuclear stability are not stable and are beta(-)? I know that a nucleus with high mass number have more neutrons than protons because the more the protons the higher the coulomb force but neutrons are not charged and can't add coulomb force in the nucleus. So why Ge(32P,41N) is more stable than it's isotope Ge(32P,46N) (which by the way has p&N even) ? Thanks in advance.