Henry Gwyn Jeffreys Moseley

"We have here a proof that there is in the atom a fundamental quantity, which increases by regular steps as one passes from one element to the next. This quantity xan only be the charge on the central positive nucleus, of the existence of which we already have definite proof." - Henry Moseley

  Henry Gwyn Jeffreys Moseley, was a skillful and talented experimental physicist. He was born in the town of Weymouth, England in 1887. His father and mother were both from well-educated families. His father was a professor of anatomy and physiology and his mother was a mollusc biologist. However, his father died when he was still very young which means that he doesn’t really get a lot of helps from his parents.

  Henry Gwyn Jeffreys Moseley studied in private schools such as his first school named Summer Fields School. By his outstanding talent, he had won a scholarship for Eton College. When he went to Eton College, he thinks that the lesson were not challenging for him and had easily won the award of physics and chemistry in Eton College.  Later on, he went to the University of Oxford’s Trinity college to have a better study on physics. However, he did not get a expected score on his final exam which he expect he will get a first class honors degree, however he get a second class honors degrees in physics that had made him disappointed for a while.

In 1910, he joined Ernest Rutherford’s research group in the University of Manchester and it is also the time that he starts to create and investigate his new discovery. Moseley taught physics and do research works at the same time, however he found out he was not even interested about teaching. Later on, Rutherford had gave him a research fellowship by his outstanding work. It gave Moseley his full attention on doing research instead of doing teaching at the same time.

• The Atomic Battery

By being one of the member in Rutherford’s research group, Moseley need to be able to familiar with radioactive chemical elements. In 1912, Moseley try to use high positive voltages to pull beta particles back into their radioactive source. By doing this, it will become more positive as the beta particles carried negative charge away. By producing about 150,000 volts on a radioactive source. He had created the first atomic battery around the world that he named it a radium battery.

• The Atomic Number

Before the discovery of Moseley about the atomic number. Dmitri Mendeleev’s periodic table was the table that the scientists used during that time of period. The elements in the periodic table were organized by their atomic weights and chemical properties. However, the atomic weight and the chemical property of an element were somehow not match with each other, so the Dmitri Mendeleev’s periodic table was organized by the properties of the elements.

However, Antonius van den Broek had bring up his hypothesis in 1911. He said that the atomic number might actually be equal to the amount of charge in the atom’s nucleus. Moseley considered the hypothesis of Antonius van den Broek and started to investigate the atomic number.  Moseley had learned that when high-energy electrons hit solids, the solids emit X-rays from William and Lawrence Bragg. In his experiment, he had used his self made equipment to shoot high-energy electrons at different chemical elements and record the wavelength and frequencies of the resulting X-rays. He found out that each element emits X-rays at a special frequency.  He get a straight line graph by plotting the square-root of X-ray frequency against elements’ atomic numbers. This result of this experiment had support and proved that the hypothesis of Antonius van den Broek was correct.

Moseley had also discovered that different elements were categorized by the number of protons that the elements have. For example, if an element has 1 proton then it must be hydrogen,  if an element has 2 proton then it must be helium…etc. By having a conclusion of elements are different by the amount of protons each element had, it was an extremely discovery in the 1900s.

By the new discovery about the atomic number from Henry Moseley, it gave all the scientists a new understanding about elements such as elements are different by the protons each element which it also means that different element will have different atomic numbers. The huge difference was made in the categorization of elements in the periodic table. It had change from organizing elements in chemical properties to atomic numbers. It had led to a huge change not just about the periodic table but the entire world of science.

Citation: 

• Home. (n.d.). Retrieved November 19, 2017, from https://www.famousscientists.org/henry-moseley/
• (n.d.). Retrieved November 19, 2017, from http://large.stanford.edu/courses/2011/ph241/yemane1/
• T. (n.d.). The Periodic Table by Rebecca Carrillo. Retrieved November 19, 2017, from https://www.thinglink.com/scene/722914036110327809
• Marshall, K. (2017, August 16). Chapter 6 The Periodic Table. Retrieved November 19, 2017, from http://slideplayer.com/slide/6035387/
• QUOTES BY HENRY MOSELEY. (n.d.). Retrieved November 19, 2017, from http://www.azquotes.com/author/55190-Henry_Moseley