فهرست عناصر بر اساس نماد اتمی; منابع اطلاعاتی عناصر شیمیایی; پانویس The element does not have any stable nuclides, and a value in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element. However, three elements, thorium, protactinium, and uranium, have a ...