Biography: * Moseley was born in Weymouth, on the south west coast of England in 1887.
His father Henry Nottidge Moseley was a naturalist, a Professor of Anatomy and physiology at Oxford and a member of the Challenger Expedition.
He attended Eton College on a King's scholarship. In 1906, he entered Trinity College of the University of Oxford, and on graduation from that institution in 1910 went to Manchester University to work with Ernest Rutherford.
During his first year at Manchester, he had a full teaching load, but after a year he started full-time research.
In 1914, Moseley resigned at Manchester to return to Oxford to pursue his research, but when World War I broke out, he enlisted in the Royal Engineers.
He fought at Gallipoli, where he was killed in by a sniper in 1915.
Many have since thought that he would have won the Nobel Prize, but was unable to because it is only awarded to the living.
It is speculated that because of Moseley's death in the War that the British and other world governments began a policy of no longer allowing their scientists to enlist for combat.
Only twenty-seven years old at death
Moseley could in many scientists' opinions have contributed much to the knowledge of atomic structure had he lived.
What did he find, What was his evidence: In 1913, by using x-ray spectra obtained by diffraction in crystals, he found a systematic relation between wavelength and atomic number, Moseley's law. Previous to this, atomic numbers or elemental numbers had been thought of as a semi-arbitrary sequential ordering-number, based on sequence of atomic masses, but altered when necessary to put an element in the appropriate place in the periodic table. For example, cobalt and nickel had been assigned atomic numbers of 27 and 28, respectively, based on their chemical properties, since they have nearly identical atomic mass (in fact, cobalt's atomic mass is larger than nickel's, which would have reversed them had they been placed in the periodic table strictly according to this criterion). Moseley's experiments were able to show directly that cobalt and nickel have clearly differing atomic numbers of 27 and 28, and are correctly placed in the periodic table by an objective measure. Moseley's discovery showed that atomic numbers were useful.
In addition, Moseley showed that there were gaps in the atomic number sequence at numbers 43, 61, 72, and 75. These spaces are now known, respectively, to be the places of the radioactive very rare elements technetium and promethium, and the last two discovered naturally-occurring stable elements hafnium (discovered 1923) and rhenium (discovered 1925). None were known in Moseley's time. Mendeleev had previously predicted technetium, and Bohuslav Brauner had previously predicted promethium; Moseley confirmed their predictions, predicted the two additional undiscovered elements, and argued that there were no other gaps in the periodic table between aluminum and gold.
The order of the Periodic Table is because of H.G.J Mosely
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Biography:
* Moseley was born in Weymouth, on the south west coast of England in 1887.
What did he find, What was his evidence:
In 1913, by using x-ray spectra obtained by diffraction in crystals, he found a systematic relation between wavelength and atomic number, Moseley's law. Previous to this, atomic numbers or elemental numbers had been thought of as a semi-arbitrary sequential ordering-number, based on sequence of atomic masses, but altered when necessary to put an element in the appropriate place in the periodic table. For example, cobalt and nickel had been assigned atomic numbers of 27 and 28, respectively, based on their chemical properties, since they have nearly identical atomic mass (in fact, cobalt's atomic mass is larger than nickel's, which would have reversed them had they been placed in the periodic table strictly according to this criterion). Moseley's experiments were able to show directly that cobalt and nickel have clearly differing atomic numbers of 27 and 28, and are correctly placed in the periodic table by an objective measure. Moseley's discovery showed that atomic numbers were useful.
In addition, Moseley showed that there were gaps in the atomic number sequence at numbers 43, 61, 72, and 75. These spaces are now known, respectively, to be the places of the radioactive very rare elements technetium and promethium, and the last two discovered naturally-occurring stable elements hafnium (discovered 1923) and rhenium (discovered 1925). None were known in Moseley's time. Mendeleev had previously predicted technetium, and Bohuslav Brauner had previously predicted promethium; Moseley confirmed their predictions, predicted the two additional undiscovered elements, and argued that there were no other gaps in the periodic table between aluminum and gold.