Ernest Rutherford By: Alex, Monita, Megan

Life: Biography Born in New Zealand on August 30, Two older brothers, older sister, and younger brother. Parents emigrated from Scotland. Father was an engineer and farmer, mother was a teacher. Earned 3 degrees at the University of Canterbury. Later traveled to England to study at the University of Cambridge. Left England for McGill University in Montreal, Canada, in He was appointed the chairman of physics. Two years later he married Mary Georgina and they had one child named Eileen. Returned to England inn 1907 for a job as the physics professor at the University of Manchester. Died on October 19, 1937.

Life: Accomplishments 1896: Discovered two distinct types of radiation, which he named alpha and beta. 1907: Discovered the nucleus. 1908: Awarded the Nobel Prize in Chemistry for his research on radioactive substances and the disintegration of the elements (he discovered the “half-life,” and used it like a clock to determine the age of the earth). 1917: Became the first person to convert one element into another when he changed nitrogen into oxygen through chemical reactions.

Life: World Events Yellowstone was established as the world’s first national park. The first color photograph was created. Alexander Graham Bell made the first successful telephone call. The Brooklyn Bridge was constructed. The rabies vaccine was developed. The Europeans colonized Africa. The Eiffel Tower was constructed. The Wall Street Journal was established. Viruses were discovered by a Russian biologist. The bubonic plague broke out in China and Australia. The X-ray machine was invented. The first modern Olympic Games were held in Athens. The first Nobel Prize ceremony was held in Sweden. The U.S. stock market crashed. Orville Wright documented the first flight of an aircraft. World War I.

Inspirations As a young chemistry and physics student, Rutherford was mentored by two scientists: Alexander Bickerton and JJ Thomson. Bickerton taught Rutherford while at the University of Canterbury, and Thomson was Rutherford’s mentor at the University of Cambridge. JJ ThomsonAlexander Bickerton

History of Chemistry JJ Thomson announced his discovery of the electron in William Thomson proposed the “plum pudding” model of the atom. He said that because atoms carry no charge, negatively charged electrons must be embedded in a cloud of positive charge. Plum Pudding model

Experiments While studying the flight of alpha particles through air (helium atom with + charge), he found that some were deflected. This inspired him to design an experiment that directed alpha particles toward a thin metal foil surrounded by a detector coated with a substance that flashes when hit by alpha particles. He predicted that the alpha particles, being so large, would crash straight through the thin gold foil. The results were very different than what he expected. Although most of the alpha particles passed straight through the foil, some were deflected at large angles, and some were reflected backwards.

Experiments

Conclusions Plum pudding model can’t be correct. Atoms have a nucleus. Rutherford created the nuclear model of the atom. Nuclear model: an atom with a dense center of positive charge (nucleus) around which tiny electrons moved in a space that was otherwise empty. The nucleus must have a positive charge to balance the negative charge of the electrons.

Questions Why are the negative electrons not attracted to the positive nucleus, causing the atom to collapse? How are the electrons arranged and how do they move?

New Findings: Neutrons In 1921 Rutherford theorized that “neutrons” cause an attractive force to keep the nucleus from breaking apart. Rutherford's theory was proved in 1932 by James Chadwick, who was awarded the Nobel Prize for this discovery in 1935.

New Findings: Bohr Model The Bohr model, created by Neils Bohr, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits on different energy levels around the nucleus (similar in structure to the solar system.)

Bibliography Introductory Chemistry book. “Ernest Rutherford.” “Ernest Rutherford.” en.wikipedia.org/wiki/Ernest_Rutherford “Ernest Rutherford – Biography.” nobelprize.org/nobel_prizes/chemistry/.../1908/rutherford- bio.html “Ernest Rutherford: Biography.” rutherford-of-nelson “History of the Atom.” toryAtom/page.htm