In physics, the atomic nucleus is the central part of an atom. In comparison to an atom, it is much smaller and contains most of the mass of the atom. The atomic nucleus also contains all of its positive electric charge (in protons), while all of its neg
The existence of the atomic nucleus was discovered by E. Rutherford in 1911 in experiments on the scattering of alpha particles upon their passage through matter. Upon observing that the alpha particles were scattered at large angles more frequently than anticipated, Rutherford hypothesized that the ...
atomic nucleusnuclear physicsnuclear reactionsBeginning in 1911, starting from the instant of the discovery of the atomic nucleus by Rutherford, physicists have made attempts to gain an understanding of the constitution of the atomic nucleus. Each nucleus is a complex unique object that consists of ...
…within an atom, a small nucleus, which generally contains both protons and neutrons, is surrounded by a swarm, or cloud, of electrons. The fundamental properties of these subatomic particles are their weight and electrical charge. Whereas protons carry a positive charge and electrons a negative...
. In this model, the positively charged nucleus was surrounded by a great deal of "empty space" 11、through which the electrons moved. In 1911, Robert Millikan conducted his "oil-drop" experiment which allowed him to measure the charge on an electron. Combining his results with those of ...
was composed of indivisible atoms, to the discovery that in the heart of each atom lies a nucleus which is ten thousand times smaller than the atom, which nonetheless carries almost all its mass, and the transformations of which involve energies that could never be reached by chemical reactions...
What is the mass of a helium-4 nucleus? What is a thermonuclear reaction in nuclear physics? What is nuclear quantum state? What particles are the result of the decay of a free (not in a nucleus) neutron? What was Rutherford's atomic theory?
nucleus: n. (pl.nucleuses,nuclei ) 核; ... The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and...
Neutrons, discovered by James Chadwick in 1932, are particles formed when a positively-charged proton and a negatively-charged electron are joined together and so have no electrical charge at all. As an example, the simplest element is hydrogen which has only a single proton in its nucleus, he...