Mass-to-charge ratio refers to the molecular or atomic mass number and "z" to the charge number of the ion; however, the quantity of "m"/"z" is dimensionless by definition. An ion of 100 atomic mass units ("m" = 100) carrying two charges ("z" = 2) will be observed at "m"/"z" = 50. In the 19th century, the mass-to-charge ratios of some ions were measured by electrochemical methods. In 1897, the mass-to-charge ratio of the electron was first measured by J. J. Thomson. By doing this, he showed that the electron was in fact a particle with a mass and a charge, and that
Given name Given name A given name (also known as a first name, forename or Christian name) is a part of a person's personal name. It identifies a specific person, and differentiates that person from the other members of a group (typically a family or clan) who have a common surname. The term "given name" refers to the fact that the name usually is bestowed upon a person, normally to a child by his or her parents at or close to the time of birth. A Christian name, a first name which historically was given at baptism, is now also typically given