The Modern View of Atomic Structure An Introduction

In the years since Thomson and Rutherford, a great deal has been learned about atomic structure. Because much of this material will be covered in detail in later chapters, only an introduction will be given here. The simplest view of the atom is that it consists of a tiny nucleus with a diameter of about 10-13 cm and electrons that move about the nucleus at an average distance of about 10 8 cm away from it (see Fig. 2.13). 

As we will see later, the chemistry of an atom mainly results from its electrons. For this reason chemists can be satisfied with a relatively crude nuclear model. The nucleus is assumed to contain protons, which have a positive 

For their work the Curies were awarded the Nobel Prize in physics in 1903, sharing the award with Henri Becquerel. In 1904, Pierre was awarded a chair in physics at the Sorbonne. He was killed tragically on the streets of Paris on April 19, 1906, when he was knocked down by a cab and the wheels of a heavy van passing in the opposite direction ran over 

Marie Curie worked tirelessly to develop radioactivity as a new discipline in physics. With the help of five assistants, she studied the effects of radioactivity and developed the atomic theory of its origin. In 1911, Marie was awarded her second Nobel Prize— this time in chemistry, for the chemical processes discovered in the identification of radium and polonium and for the subsequent characterization of these elements. During World War I, she trained doctors in the new methods of radiology and, after learning to drive, personally transported medical equipment to hospitals. After the war, Madame Curie assumed leadership of the newly built Radium Institute in Paris. In 1920, a campaign was mounted in the United States to produce 1 gram of radium for Marie to support her research. She traveled to the United States to receive the precious vial of radium at the White House in 1921. 

Marie Curie continued her studies of radioactivity until just before her death of leukemia in 1934. She was truly one of the greatest scientists of the twentieth century.  

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