For a positron decay and also for an alpha decay ( see below ), the oblique arrow would go from right to left since in these cases, the proton number decreases.
12.
Nuclear isomers are members of a set of nuclides with equal proton number and equal mass number ( thus making them by definition the same isotope ), but different states of excitation.
13.
Although its proton number of 58 is not magic, it is granted additional stability, as its eight additional protons past the magic number 50 enter and complete the 1 g 7 / 2 proton orbital.
14.
It is useful to think of the decay scheme as placed in a coordinate system, where the ordinate axis is energy, increasing from bottom to top, and the abscissa is the proton number, increasing from left to right.
15.
One possible magic number of neutrons for spherical nuclei is 184, and some possible matching proton numbers are 114, 120 and 126 which would mean that the most stable spherical isotopes would be flerovium-298, unbinilium-304 and unbihexium-310.
16.
But with that exception, all elements with proton numbers greater than the 92 of uranium must be made in laboratories, and with Element 114, 21 artificial elements have been made . ( Element 113 is missing from the sequence .)
17.
In contrast, the proton numbers for which there are no stable isotopes are primordial radionuclide are 27 ( 50 V ), 65 ( 113 Cd ), 81 ( 138 La ), 85 ( 147 Sm ), and 105 ( 176 Lu ).
18.
Of course, the change in properties is miniscule, compared to that found by changing proton number ( heavy water is far more like water than Hydrogen sulfide ( H 2 S ), which boils at below room temp and kills in tiny doses ! ), so for every day chemistry, the effects are ignored.
19.
The modern version of Prout's rule is that the atomic mass of an isotope of proton number ( atomic number ) " Z " and neutron number " N " is equal to sum of the masses of its constituent protons and neutrons, minus the mass of the nuclear binding energy, the mass defect.
20.
In general, the mass number of a given nuclide differs in value slightly from its atomic mass, since the mass of each proton and neutron is not exactly 1 " u "; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and ( finally ) because of the nuclear binding energy.
