Analysis of Hydrocarbons by Means of the Mass Spectrometry. V. Fragmentation of Monocyclic Hydrocarbons as a Function of the Ring SizeThe E.I.‐spectra of the cycloalkanes CnH2n(n = 5 – 14) and of the cycloalkenes CnH2n‐2(n = 5 – 12) exhibit strongly influence of the ring strain energies on the stability of molecular ions. Medium‐sized cycloalkanes and cycloalkenes (n = 9 – 11) show exceptional behaviour under the conditions of the electron impact ionization, which is discussed on the base of ring str