Atom to the positively charged nucleus by the attraction created from opposite electric charges. If an atom has more or fewer electrons than its atomic number, then it becomes respectively negatively or positively charged as a whole; a charged atom is called an ion. Electrons have been known since the late 19th century, mostly thanks to J.J. Thomson; see history of subatomic physics for details. Protons have a positive charge and a mass 1,836 times that of the electron, at . The number of protons in an atom is called its atomic number. Ernest Rutherford (1919) observed that nitrogen under alpha-particle
Empire of the Atom bodily" from the plot of "I, Claudius". A genealogy chart of the ruling family of the Empire of Linn is included. Van Vogt based "Empire of the Atom" largely on the plot of "I, Claudius" by Robert Graves, putting it into a science-fictional setting. The work was originally presented as five novelettes published in "Astounding Science Fiction" between May 1946 and December 1947. Some time, a little over 10,000 years from now, a noblewoman gives birth to a deformed child, a consequence of having been accidentally exposed to radiation from one of the temples of the Atom Gods. The baby