Ionic radius, r ion, is the radius of an atom's ion.Although neither atoms nor ions have sharp boundaries, they are sometimes treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion gives the distance between the ions in a crystal lattice.herefore, the distance between the Na + and Cl â ions is half of 564.02 pm, which is 282.01 pm. However, although X-ray crystallography gives the distance between ions, it doesn't indicate where the boundary is between those ions, so it doesn't directly give ionic radii.
As the wife of Alexander Graham Bell, an eminent scientist and the inventor of the first practical telephone, she took the married name Mabel Bell. From the time of Mabel's courtship with Graham Bell in 1873, until his death in 1922, Mabel became and remained the most significant influence in his life.
Here are some resources you can use to learn more about Alexander Graham Bell and the telephone: The Biography of Alexander Graham Bell from Biography.com. A Very Detailed Biography of Alexander Graham Bell from History.com. Good Biographical Information on Alexander Graham Bell. The Encyclopedia Britannica Entry on Alexander Graham Bell and the History of the Telephone  and the History of the Telephone  was born on March 3, 1847, in Edinburgh, Scotland. He had two brothers, but both passed away from tuberculosis by the time Bell was 20 years old. When he was born, his given name was just Alexander Bell. Both of his brothers had middle names, and Alexander pleaded with his father for a middle name as well. When Bell was 11 years old, his father allowed him to take the middle name of Graham, which was the last name of a family friend.