what was the former's contribution to this field of study?
He came to be known as the father of nuclear physics. He discovered the concept of radioactive half-life, the radioactive element radon, and differentiated and named alpha and beta radiation.
Ernest Rutherford
 came to be known as the father of nuclear physics. "Encyclopædia Britannica" considers him to be the greatest experimentalist since Michael Faraday (1791–1867).

In early work, Rutherford discovered the concept of radioactive half-life, the radioactive element radon, and differentiated and named alpha and beta radiation. 
where are electrons found in an atom and what electrical charge and mass do they have An electron can be "bound" to the nucleus of an atom by the attractive Coulomb force.  If the number of electrons is different from the nucleus' electrical charge, such an atom is called an ion. which theory explains or is based on this? Atomic Theory, Quantum Theory what exactly is the part of the atom mentioned above, initially? The electron is a subatomic particle, whose electric charge is negative one elementary charge. who discovered that it has two charges? French chemist Charles François du Fay what is this particle mentioned above? Subatomic particles are smaller than atoms. They can be composite particles, such as the neutron and proton; or elementary particles, which according to the standard model are not made of other particles. what method is used to divide the atom? Nuclear physics where was the chemist mentioned above born? France did he publish any books? Yes, All Du Fay's publications appeared in the journal "Histoire de l'Académie Royale des Sciences: avec les mémoires de mathématique & de physique pour les mêmes années" who are some well -known scientists in the branch of physics mentioned above? Ernest Rutherford, Hans Geiger
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Ernest Rutherford [SEP] Introduction
Rutherford moved in 1907 to the Victoria University of Manchester (today University of Manchester) in the UK, where he and Thomas Royds proved that alpha radiation is helium nuclei. Rutherford performed his most famous work after he became a Nobel laureate. In 1911, although he could not prove that it was positive or negative, he theorized that atoms have their charge concentrated in a very small nucleus, and thereby pioneered the Rutherford model of the atom, through his discovery and interpretation of Rutherford scattering by the gold foil experiment of Hans Geiger and Ernest Marsden. He performed the first artificially induced nuclear reaction in 1917 in experiments where nitrogen nuclei were bombarded with alpha particles.