A mole is a measurement of a ‘batch’ of particles. It is easier to describe the number of moles of a substance rather than the number of atoms as atoms are very small. Relative atomic mass is the ...

The relative masses of atoms give information about the binding energies of their component particles. By precise comparison of the masses of two atoms which differ by one or two nucleons, the binding ...

THE multipole lines from atomic sulphur are of considerable astrophysical interest. Moreover, a direct measurement of their wavelength is the best and most direct method of fixing the positions of the ...