[AntonioLao]

In chemistry, the capital letter A stands for atomic mass number. The capital letter Z stands for the number of protons inside a specific nucleus. The capital letter N stands for the number of neutron inside the same nucleus except hydrogen where there is no neutron. The atomic mass number is then defined as the sum of Z and N: A = Z + N. Incidentally, Z is also the number of electrons inside neutral atoms.

For stable chemical elements, although Z varies continuously from 1 for hydrogen to 106 for seaborgium, A varies from 1 for hydrogen to 263 for seaborgium. However, there are gaps of more than 50% missing atomic mass numbers: 2, 3, 5, 6, 8, 10, 13, 15, 17, 18, 21, 22, 25, 26, 29, 30, 33, 34, 35, 37, 38, 41, 42, 43, 44, 46, 47, 49, 50, 53, 54, 55, 57, 58, 60, 61, 62, 63, 66, 67, 68, 69, 71, 72, 74, 76, 77, 78, 81, 82, 83, 86, 87, 90, 92, 94, 95, 97, 99, 100, 102, 104, 105, 107, 109, 110, 111, 113, 114, 116, 117, 118, 120, 121, 123, 124, 125, 126, 127, 128, 129, 130, 132, 134, 135, 136, 138, 142, 143, 146, 147, 148, 149, 151, 153, 154, 155, 156, 158, 160, 161, 162, 164, 166, 168, 170, 171, 172, 174, 176, 177, 178, 180, 182, 183, 185, 187, 188, 189, 191, 193, 194, 196, 198, 199, 200, 202, 203, 205, 206, 208, 211, 212, 213, 214, 215, 216, 217, 318, 219, 220, 221, 224, 225, 228, 229, 230, 232, 233, 234, 235, 236, 239, 240, 241, 242, 245, 246, 248, 249, 250, 253, 254, 255, and 256. There is no plausible explanation why this is happening. On the other hand, if radioisotopes are introduced many of these gaps can be filled, see Table 26-1 of Linus Pauling’s General Chemistry, p846-47, Dover Edition, 1988. But still their half-lives can vary as brief as a millionth quadrillionth of a second to as long as 5760 years for carbon-14.

Nevertheless, using the principle of even number conservation of space-time charges, these mass gaps can be explained as violations of the principle when there are odd multiples of the total space-time charges of the neutron ( 7, 7 ) configuration.