every element has a uniquely characteristic atomic           spectrum?
929125
Every element gives a a different wavelength of light when its electrons are excited.  When electrons are excited they want to get rid of all that extra energy to return to ground state.  That amount of energy is unique to that atom and that state of the electron the release of energy is in the form of light, visible and non visible
59388
The periodic table as of Oct. 2005 according to IUPAC shows 111. But the elements with atomic numbers 112, 114, and 116 have been reported but not have not been fully authenticated as of September 2003 (Pure Appl. Chem. 75(10), pp. 1601-1611, 2003).
817102
They're constantly adding new ones.  The new ones are synthetically created by bombarding already existing elements with neutrons.  Apparently, they're up to atomic no. 118, now:\n\nhttp://www.webelements.com/webelements/scholar/
1164287
GIVE ME TEN POINTS!!!  \n\nHERES UR GROUPS....\n\n\nGroup 0 Elements\nThe elements in this group have a full outer electronic shell and thus, the elements in this group have no tendency to lose, gain or share electrons. Thus, the elements in the group are chemically inert. \n\nAll the elements in this group are gaseous. Because of their chemical inertness, the elements in this group are called the Nobel Gases : \n\n\nHelium\nNeon\nArgon\nKrypton\nXenon\nRadon \n\n\n--------------------------------------------------------------------------------\n\nGroup I Elements\nThe elements in this group have one electron in their outer electronic shell. Thus, each element in this group has a tendency to lose a single electron, to form a singly charged positive ion, which has the stable electronic configuration of its neighbouring Nobel Gas element in the periodic table. \n\nThe elements in the group are chemically reactive. \n\nThe group is divided into two sub-groups. \n\nSub-Group Ia : The Alkali Metals\n\nLithium\nSodium\nPotassium\nRubidium\nCaesium\nFrancium\n\n\nSub-Group Ib : Transition Metal Elements\n\nCopper\nSilver\nGold\n\nHydrogen is included in this group because it has a single electron in its outer electronic shell. However, hydrogen has none of the metallic properties of the alkali metals. \n\n\n\n--------------------------------------------------------------------------------\n\nGroup II Elements\nThe elements in this group have two electrons in their outer electronic shell. Thus, each element in this group has a tendency to lose two electron, to form a doubly charged positive ion, which has the stable electronic configuration of its neighbouring Nobel Gas element in the periodic table. \n\nThe elements in the group are chemically reactive. \n\n\nSub-Group IIa : The Alkaline Earth Metals\n\nBeryllium\nMagnesium\nCalcium\nStrontium\nBarium\nRadium\n\n\nSub-Group IIb : Transition Metal Elements\n\nZinc\nCadmium\nMercury\n\n\n\n--------------------------------------------------------------------------------\n\nGroup III Elements\nThe elements in this group have three electrons in their outer-most electronic shell. The electronic configurations of the n th orbitals (i.e. outer-most orbitals) are ns2 np1. Thus, each element in this group has a tendency to lose three electron, to form a triply charged positive ion, which has the stable electronic configuration of its nearest neighbouring Nobel Gas element in the periodic table. \n\nThe elements in the group are chemically reactive. \n\n\nSub-Group IIIa : Transition Metal Elements\n\nScandium\nYttrium\nLanthanum\n\nThe following elements also have the same electronic configuration as lanthanum (i.e. 4s2 4p1) in their outer-most electronic orbitals, while the inner 3d orbitals are being filled, from going from element to element.\nCerium\nPraeseodymium\nNeodymium\nPromethium\nSamarium\nEuropium\nGadolinium\nTerbium\nDysprosium\nHolmium\nErbium\nThulium\nYtterbium\nLutecium\n\n\nThese are the transition elements, and are also called the Lanthanides. \n\nActinium\n\nThe following elements also have the same electronic configuration as actinium (i.e. 5s2 5p1) in their outer-most electronic orbitals, while the inner 4d orbitals are being filled, on going from element to element.\nNeptunium\nPlutonium\nAmericium\nCurium\nBerkelium\nThese are the inner transition elements, and are also called the Actinides. \n\n\nSub-Group IIIb : Main Group Elements\n\nBoron\nAluminium\nGallium\nIndium\nThallium\n\n\n\n--------------------------------------------------------------------------------\n\nGroup IV Elements\nThe elements in this group have four electrons in their outer electronic shell. Thus, each element in this group has a tendency to share these four electrons, to form covalent compounds, thereby gaining the stable electronic configuration of its neighbouring Nobel Gas element in the periodic table. \n\nThe elements in the group are chemically reactive. \n\nSub-Group IVa : Transition Me
518213
atoms because everything in the world is actually atoms
435134
So, I don't think we have the technology to actually know if two atoms are identical.  Right now, we just think they are based on various observations.  It could turn out that each atom is actually a mini solar system like you suggested or it could turn out to be just identical atoms.  Science is just a series of guesses based on our current observations.  It changes all the time.
789494
Basic Atomic Structure\n\nThe definitions of atoms and elements seems, at first glance, almost circular: an element is a substance made up of only one kind of atom, and an atom is the smallest particle of an element that retains all the chemical and physical properties of the element. In fact, these two definitions do not form a closed loop, as they would if it were stated that an element is something made up of atoms. Every item of matter that exists, except for the subatomic particles discussed in this essay, is made up of atoms. An element, on the other hand, is—as stated in its definition—made up of only one kind of atom. "Kind of atom" in this context refers to the number of protons in its nucleus.\n\nProtons are one of three basic subatomic particles, the other two being electrons and neutrons. As we shall see, there appear to be particles even smaller than these, but before approaching these "sub-subatomic" particles, it is necessary to address the three most significant components of an atom. These are distinguished from one another in terms of electric charge: protons are positively charged, electrons are negative in charge, and neutrons have no electrical charge. As with the north and south poles of magnets, positive and negative charges attract one another, whereas like charges repel. Atoms have no net charge, meaning that the protons and electrons cancel out one another.
1106361
If you allow other elements, many hundreds can be formed, some probably have never been made or identified.  The simple ones can be found at\n\nhttp://www.webelements.com/webelements/elements/text/Sb/comp.html
333129
An element will become stable when it's outermost electron (valence) shell is full.  In most cases, the valence shell will contain 8 electrons when stable.  Hydrogen and helium only require 2 electrons.  \n\nIn order to achieve a full set, atoms can gain or lose electrons forming ionic compounds.  This normally happens between metals and nonmetals on the periodic table.  Alternatively, atoms can share electrons forming covalent compounds, which generally occurs between two nonmetals.
696104
No; very few isotopes have been given individual names (there are far too many of them). The only ones I can think of are deuterium (hydrogen-2) and tritium (hydrogen-3).
396592
A continuous spectrum of what?
403502
Here is one : http://en.wikipedia.org/wiki/Periodic_table
1169808
The periodic table is organized by a few things, but most noticably is the amount of protons located in the nucleus of an atom.\n\n1 Hydrogen, 2 Helium, 3 Lithium, 4 Beryllium, 5 Boron etc\n\nYour question cannot be answered unless we found that there was a limit to the number of protons allowed to be in the nucleus.  As of right now, there is no pursuading evidence that there couldn't be an element with 603 protons, 2005 protons etc...\n\nSo we must admit that there could be an infinite amout of elements (though in the real world there isn't anything that is "Infinite") so theoretically we know 111 elements out of infinity. \nWhich is 0%.
897762
Element talks about the chemical identity.  How one atom is not like another.\nAtom talks about the particular entities.\n\nElement is a general term while atom is a specific term.\nSo you can speack of the element so and so and be describing the substance and its properties for example as that element is in all the universe.
783521
Anything from the periodic table is pure. these are all basic elements that can't be broken down into other elements. examples: hydrogen, nitrogen, iron, zinc and gold.\nclick here for the table: http://www.chem.qmul.ac.uk/iupac/AtWt/table.html
24017
With modern chemistry and quantum physics knowledge, we know 104 elements. \n\nAn element is defined by proton count, which in turn determines the number of electrons in orbit. Hence we know we aren't missing any elements in between, all numbers between 1 and 104 are known.\n\nThis leaves elements with proton counts of 105 or greater. The greatest difficulty in identifying these is that they are extremely unstable. The observer needs to be lucky and skilled to observe one of these superheavy elements before it decays.\n\nEven more so since these elements are produced by colliding heavy ions at high speed, creating lots of  energy at the collision. Capturing such an element and identifying its mass charge ration in a mass spectrometer or getting spectroscopical data that can be fitted to the theoretical energies one would expect is hard under these circumstances.
746306
Elements consist of a single type of atom.  For example, pure iron has only iron atoms.  Compounds combine more than one type of atom, for example, iron and oxygen form a compound called iron oxide, also known as rust.  Elements and compounds are alike because they cannot be separated into different materials by mechanical means, like filtering, magnetic separation or picking with tweezers.  The are different in that element have only one kinds of atom, while compounds have two or more types of atoms.  Even when you have material which is all one type of atom, such as a hydrogen gas cloud, a distinction is made between "elemental hydrogen", which is extremely reactive, and H2, which might need an outside source of energy to cause it to react with another element.