A Level Chemistry Mass Spectrometry

Yes, 72 is the relative formula mass because remember small molecular peaks are usually unstable molecular fragments because if you look at a mass spec graph the final major peak is considered as the relative formula mass of the molecule any peak smaller than the Final major peaks are considered as unstable isotopic peaks.
and it is Electrospray Ionisation because electron impact is only used for molecules with low formula mass and electron spray is used on large formula molecules to prevent a lot of fragmentation which would occur with low formula mass molecules.

Yes, 72 is the relative formula mass because remember small molecular peaks are usually unstable molecular fragments because if you look at a mass spec graph the final major peak is considered as the relative formula mass of the molecule any peak smaller than the Final major peaks are considered as unstable isotopic peaks.
and it is Electrospray Ionisation because electron impact is only used for molecules with low formula mass and electron spray is used on large formula molecules to prevent a lot of fragmentation which would occur with low formula mass molecules.

My teacher says that we don’t need to learn this yet, however I am really confused about how it can be solved. The question is: all particles have the same kinetic energy (=1/2 mv2, where m=mass of the particle and v= velocity) and the velocity of the particles is given by v=d/t (where d=distance travelled and t= time taken). If the time of flight of a 54Cr+ ion is 1.486 x 10-5 seconds, calculate the time of flight of a 50Cr+ ion. Give your answer to the appropriate sig figs. Any help would be appreciated