magic neutron number

A "magic neutron number" refers to specific counts of neutrons in an atomic nucleus that lead to notably stable configurations. Just like certain numbers make building blocks more stable, these neutron counts create a more tightly bound nucleus, making it less likely to decay or break apart. These magic numbers—such as 2, 8, 20, 28, 50, 82, and 126—arise from quantum effects that fill energy levels within the nucleus, resulting in increased stability. This concept helps scientists understand why some isotopes are more common or longer-lasting than others.