Search results
Results from the WOW.Com Content Network
If an atom has more electrons than protons, then it has an overall negative charge, and is called a negative ion (or anion). Conversely, if it has more protons than electrons, it has a positive charge, and is called a positive ion (or cation). The electrons of an atom are attracted to the protons in an atomic nucleus by the electromagnetic force.
Protons define the entire charge of a nucleus, and hence its chemical identity. Neutrons are electrically neutral, but contribute to the mass of a nucleus to nearly the same extent as the protons. Neutrons can explain the phenomenon of isotopes (same atomic number with different atomic mass). The main role of neutrons is to reduce electrostatic ...
Throughout the 1800's speculative ideas about atoms were discussed and published. JJ Thomson 's model was the first of these models to be based on experimentally detected subatomic particles. In the same paper that Thomson announced his results on "corpuscle" nature of cathode rays , an event considered the discovery of the electron , he began ...
Atoms are the smallest neutral particles into which matter can be divided by chemical reactions. An atom consists of a small, heavy nucleus surrounded by a relatively large, light cloud of electrons. An atomic nucleus consists of 1 or more protons and 0 or more neutrons. Protons and neutrons are, in turn, made of quarks.
All elements have multiple isotopes, variants with the same number of protons but different numbers of neutrons. For example, carbon has three naturally occurring isotopes: all of its atoms have six protons and most have six neutrons as well, but about one per cent have seven neutrons, and a very small fraction have eight neutrons. Isotopes are ...
Alternatively, one can adopt the protons, neutrons, and electrons definition. Based on protons, neutrons and electrons A definition of "matter" more fine-scale than the atoms and molecules definition is: matter is made up of what atoms and molecules are made of , meaning anything made of positively charged protons , neutral neutrons , and ...
For example, a neutral chlorine atom has 17 protons and 17 electrons, whereas a Cl − anion has 17 protons and 18 electrons for a total charge of −1. All atoms of a given element are not necessarily identical, however. The number of neutrons may vary to form different isotopes, and energy levels may differ, resulting in different nuclear ...
The decay of a neutron within a nuclide is illustrated by the decay of the carbon isotope carbon-14, which has 6 protons and 8 neutrons. With its excess of neutrons, this isotope decays by beta decay to nitrogen-14 (7 protons, 7 neutrons), a process with a half-life of about 5,730 years. [37] Nitrogen-14 is stable. [38]