a New Zealand physicist who was a pioneering researcher in both atomic and nuclear physics. He has been described as "the father of nuclear physics",[8] and "the greatest experimentalist since Michael Faraday". Together with H.G. Moseley, he developed the atomic numbering system in 1913, identified the inner working of the atom and discovered the positive-charged particle, the Proton
He discovered essential nature of the atomic nucleus was established with the discovery of the neutron in 1932 and the determination that it was a new elementary particle, distinct from the proton.
[Ne} 3s2
[Ne} 3s2 3p4
He advanced the theory of electrons traveling in orbits of quantized "stationary states" around the atom's nucleus in order to stabilize the atom, but it wasn't until his 1921 paper that he showed that the chemical properties of each element were largely determined by the number of electrons in the outer orbits of its atoms.
He introduced the idea that an electron could drop from a higher-energy orbit to a lower one, in the process emitting a quantum of discrete energy.
[Ne} 3s2 3p6
Verticales
[He} 2s2 2p3
Electrons in the outermost shell of an atom, and that can participate in the formation of a chemical bond if the outermost shell is not closed.
In the early 20th century, this American chemist began to use dots in lecture, while teaching undergraduates at Harvard, to represent the electrons around atoms.
His students favored these drawings, which stimulated him in this direction. From these lectures, he noted that elements with a certain number of electrons seemed to have a special stability. This phenomenon was pointed out by the German chemist Richard Abegg in 1904, to which he referred to as "Abegg's law of valence" (now generally known as Abegg's rule). It appeared that once a core of eight electrons has formed around a nucleus, the layer is filled, and a new layer is started. He also noted that various ions with eight electrons also seemed to have a special stability. On these views, he proposed the rule of eight or octet rule: Ions or atoms with a filled layer of eight electrons have a special stability.
[Ne} 3s1
[Ne} 3s2 3p2
[Ne} 3s2 3p3
His experiments suggested not only that cathode rays were over 1,000 times lighter than the hydrogen atom, but also that their mass was the same in whichever type of atom they came from. He concluded that the rays were composed of very light, negatively charged particles which were a universal building block of atoms. He called the particles "corpuscles", but later scientists preferred the name electron which had been suggested by George Johnstone Stoney in 1891.
[Ne} 3s2 3p5
a positively charged ion
[He} 2s2
He introduced the atomic theory into chemistry:
1.) Elements are made of extremely small particles called atoms.
2.) Atoms of a givbn element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.
3.) Atoms cannot be subdivided, created or destroyed.
4.) Atoms of different elements combine in simple whole-number ratios to form chemical compounds.
5.) In chemical reactions, atoms are combined, separated or rearranged.
[Ne} 3s2 3p1
Electron Configuration Notation
1s2
[He} 2s2 2p1
[He} 2s2 2p6
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