Nounatom (plural atoms)
Synonyms
Related termsFrom Wiktionary under the GNU Free Documentation License. The atom is a basic unit of matter that consists of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive or negative charge and is an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element. The name atom comes from the Greek "ἄτομος"—átomos (from α-, "un-" + τέμνω - temno, "to cut"), which means uncuttable, or indivisible, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was divisible. The principles of quantum mechanics were used to successfully model the atom. Atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.9% of an atom's mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass. Each element has at least one isotope with unstable nuclei that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus. Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties. From Wikipedia under the
GNU Free Documentation License  calgaryherald.com unknown Fri, 03 Sep 2010 12:14:03 GM The head of the UN nuclear watchdog has invited Israel to consider joining a global anti-nuclear arms. From Google Blog Search: "atom"  thefutureofthings.com Fri, 27 Aug 2010 13:08:21 GMT+00:00 and Molecules from the Inside Out The Future of Things An international team of scientists recently published surprising results regarding atoms ' structure, showing that it's possible to create hollow atoms by ...  opednews.com Fri, 27 Aug 2010 19:55:39 GMT+00:00 OpEdNews ... to halt uranium enrichment -- the process which can be used to make nuclear fuel but also the fissile core of an atom bomb in highly purified forms. ...  edn.com Fri, 27 Aug 2010 12:05:41 GMT+00:00 EDN.com Further, Samsung has become a major supplier of application processors based on cores licensed from ARM, which compete with Intel's Atom processors in smart ... From Google News Search: "atom"  atomage.net 334px x 500px | 39.20kB [source page] atomgas27 jpg 18 Jan 2008 09 55 35k atom dentgas 20 jpg 18 Jan 2008 09 55 35k atom dentgas 14 jpg 18 Jan 2008 09 55 39k atom dentgas7 jpg 18 Jan 2008 09 55 39k  bluesuncorp.co.uk 810px x 890px | 141.40kB [source page] Woman chin Reminds me of an incident a while back in BoM when a joke picture was posted of one of the clanmates and debate still rages as to the gender of the pictured http bluesuncorp co uk photowall atom jpg I strongly maintain that the jawline and faint lip hair means it is a man Others think differently From Yahoo Image Search: "atom" What is the photon wavelength that a hydrogen atom will absorb? Q. I have read that atoms can absorb photons which will raise the atom to a higher energy level, but only if you can match the photon energy to one of the steps of the atom exactly. So, What photon wavelength will the hydrogen atom absorb? Asked by Brad K - Wed Jun 18 09:43:39 2008 - - 1 Answers - 0 Comments A. It can absorb many different wavelengths. The energy of the hydrogen atom is: Rydberg energy * (1 / n^2), where n is any integer. So possible transitions are: delta E = hf = hc / wavelength = Rydberg energy (1 / n1^2 - 1 / n2^2) So wavenelngth = hc * n1^2 n2^2 / (RydbergEnergy(n1^2 - n2^2)) where R is Answered by ( )Mistress Bekki - Wed Jun 18 09:54:42 2008 What kinds of physicists deal with the atom and the nucleus? Study the atomic structure of an atom and energy? Q. Im in high school and I want to get into a career that studies the atom and the nucleus. Does anyone know what does physicists are called and what fields they can work in? Asked by Businessman - Tue Sep 4 20:47:34 2007 - - 2 Answers - 0 Comments A. It's called Nuclear Physics. It's best to also study a lot of Chemistry, because of at that small of a level, they are related. You can then become a Nuclear Scientist. Wow, sounds great, doesn't it! . Answered by KYRA - Tue Sep 4 20:55:45 2007 What are two different ways a carbon atom from a blade of grass could become a part of a cell in your ear?
Q. I have a theory: You're lying down on the grass and an ant crawls inside your ear. There is a carbon atom attached to the ant. Then the ant dies. Since there are no decomposeres, the ant just stays there. Slowly, the atom comes off the ant and goes into the ear. Any better suggestions? Asked by Sugar Candy - Sun Sep 20 16:41:36 2009 - - 1 Answers - 0 Comments A. Your teacher will not like your answer, I guarantee that. Try these: 1. The grass is eaten by a free-range dairy cow. The grass is chewed and digested by the cow, and the simple sugars from the grass are absorbed by the cow. They are broken down, and the carbon atom in question is built up by the cow's udder to become part of a fatty acid as part of a fat in its milk. The cow is milked. You drink whole milk, digest and absorb the fatty acids. The carbon atom, as part of a small fatty acid, proceeds through your circulatory system to your ear. It is absorbed by a cell in your ear, and incorporated into a membrane phospholipid molecule there. 2. The grass dries in late summer, and a brush fire sends the carbon atom into the air as… [cont.] Answered by emucompboy - Sun Sep 20 17:03:45 2009 From Yahoo Answer Search: "atom" |
