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An atom is a body which cannot be cut in two; a molecule is the smallest possible portion of a particular substance. After speaking about the atomic theory of Democritus, Maxwell goes on to tell us that the word 'molecule' is a modern word. He states, "it does not occur in Johnson's Dictionary. The ideas it embodies are those belonging to ...
A Boy and His Atom is a 2013 stop-motion animated short film released on YouTube by IBM Research. One minute in length, it was made by moving carbon monoxide molecules with a scanning tunneling microscope , a device that magnifies them 100 million times.
Dalton defined an atom as being the "ultimate particle" of a chemical substance, and he used the term "compound atom" to refer to "ultimate particles" which contain two or more elements. This is inconsistent with the modern definition, wherein an atom is the basic particle of a chemical element and a molecule is an agglomeration of atoms.
Rutherford had already revealed the structure of an atom to consist mostly of empty space with a dense nucleus of protons at the centre, and Henry Mosley had shown that it is the number of protons that gives an atom its identity as a particular element. An atom of the element carbon has 6 protons, whilst an atom with 7 protons is one of nitrogen.
GCSE Bitesize was launched in January 1998, covering seven subjects. For each subject, a one- or two-hour long TV programme would be broadcast overnight in the BBC Learning Zone block, and supporting material was available in books and on the BBC website. At the time, only around 9% of UK households had access to the internet at home.
Joseph Priestley and Antoine Lavoisier discover a new gas called oxygen, discrediting the basic theory of chemistry at the time, creating the basis for the modern science of chemistry, and prompting chemists all over the world to look for more new elements; Humphry Davy introduces audiences to nitrous oxide ("laughing gas") and uses electricity to search for new chemical elements.
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 January 2025. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and extended ...
It has a mass much greater than had been previously expected — almost as great as a gold atom. 1995 The D0 and CDF experiments at the Fermilab Tevatron discover the top quark . 1998 – The Super-Kamiokande (Japan) detector facility reports experimental evidence for neutrino oscillations , implying that at least one neutrino has mass.