Search results
Results from the WOW.Com Content Network
The nucleus of an atom consists of neutrons and protons, which in turn are the manifestation of more elementary particles, called quarks, that are held in association by the nuclear strong force in certain stable combinations of hadrons, called baryons. The nuclear strong force extends far enough from each baryon so as to bind the neutrons and ...
The precision measurement made by Leonard Ornstein, the director of Utrecht's Physical Laboratory, showed that the spin of nitrogen nucleus must be equal to one. However, if the nitrogen-14 (14 N) nucleus was composed of 14 protons and 7 electrons, an odd number of spin-1/2 particles, then the resultant nuclear spin should be half-integer ...
The atomic nucleus shown expanded more than 10,000 times its size relative to the atom; electrons have no measurable diameter. The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus.
The number of protons in an atom (which Rutherford called the "atomic number" [27] [28]) was found to be equal to the element's ordinal number on the periodic table and therefore provided a simple and clear-cut way of distinguishing the elements from each other. The atomic weight of each element is higher than its proton number, so Rutherford ...
One product of the reaction was the proton; the other product was shown by Patrick Blackett, Rutherford's colleague and former student, to be oxygen: 14 N + α → 17 O + p. Rutherford therefore recognised "that the nucleus may increase rather than diminish in mass as the result of collisions in which the proton is expelled". [56]
Otto Robert Frisch was born in Vienna in 1904 to a Jewish family, the son of Justinian Frisch, a painter, and Auguste Meitner Frisch, a concert pianist. [4] He himself was talented at both but also shared his maternal aunt Lise Meitner's love of physics and commenced a period of study at the University of Vienna, graduating in 1926 with some work on the effect of the newly discovered electron ...
The prevailing model of atomic structure before Rutherford's experiments was devised by J. J. Thomson. [2]: 123 Thomson had discovered the electron through his work on cathode rays [3] and proposed that they existed within atoms, and an electric current is electrons hopping from one atom to an adjacent one in a series.
These spaces are now known, respectively, to be the places of the radioactive synthetic elements technetium and promethium, and also the last two quite rare naturally occurring stable elements hafnium (discovered 1923) and rhenium (discovered 1925). Nothing was known about these four elements in Moseley's lifetime, not even their very existence.