The British physicist, Henry Moseley is known for his establishment of truly scientific basis of the Periodic Table of the Elements by sorting chemical elements in the order of their atomic numbers. In his short career, he contributed a lot towards the science of physics through his research. Many scientists believe that if Moseley had survived a bit longer he would have contributed a great deal to the knowledge of atomic structure and also earned the Nobel Prize in Physics.
Henry was born in Weymouth, Dorset, on the southwestern coast of England on November 23, 1887. He belonged to a rich, aristocratic, and scientifically accomplished family. Henry Nottidge Moseley, his father was a biologist and also a professor of anatomy and physiology at the University of Oxford. Henry’s mother, Amabel Gwyn-Jeffreys Moseley was the daughter of the biologist and conchologist John Gwyn Jeffreys. It was not a surprise when Henry showed his interest in zoology.
Moseley was always a very bright student. He received a King’s scholarship to attend Eton College where he excelled in mathematics, and was introduced to the study of x rays by his physics teacher. In 1910, he graduated from Trinity College of the University of Oxford after which he earned a position in the laboratory of Ernest Rutherford at the University of Manchester under the supervision of professors such as Sir Ernest Rutherford.
Contributions and Achievements:
In 1913, while working at the University of Manchester, Moseley observed and measured the X-ray spectra of various chemical elements obtained by diffraction in crystals. Through this he discovered a systematic relation between wavelength and atomic number. This discovery is now known as the Moseley’s law. Before his finding, atomic numbers had been thought of as an arbitrary number, based on sequence of atomic weights. Moseley also predicted a number of missing elements and their periodic numbers in the Periodic Table.
His method in early X-ray crystallography was able to sort out many chemical problems promptly, some of which had confused chemists for a number of years. Both the apparent irregularities in the location of elements such as argon and potassium and the positioning of the rare earth (inner transition) elements in the periodic table could now be elucidated on the basis of atomic number.
Moseley is also known for the development of of early X-ray spectrometry equipment which he learnt to design with the help of William Henry Bragg and William Lawrence Bragg at the University of Leeds. This device basically consisted of glass-bulb electron tube in which the ionization of electrons caused the emission of X-rays photons finally resulting in photographic lines.
In 1914, Henry Mosely planned to continue his physics reasearch at Oxford so he resigned from his position at Manchester. His plans were never materialised because when the first World War broke out he decided to enlist in the British Army. On August 10, 1915 he was shot dead during the Battle of Gallipoli, in Turkey.
This great physicist died very young at the age of twenty-seven but his contribution to the scientific world will never be forgotten.