which element has the lowest atomic mass?
964215
Hydrogen (1.008) consisting of hydrogen (1 electron and 1 proton, with small amounts of isotopes deuterium (heavy hydrogen (1 electron 1 proton and 1 neutron))  and tritium (radioactive (1 electron 1 proton and 2 neutrons))\n\nDeuterium comprises 0.0026–0.0184% of all hydrogen on Earth\n\nTritium is radioactive, decays through beta decay with a half-life of 12.32 years. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases; tritium has also been released during nuclear weapons tests
497438
The atomic number is equal to the number of protons.\nThe mass number is equal to protons plus neutrons.\n\nThe difference between those two numbers would equal the number of neutrons.
988938
Matter (116 Elements known so far) (94 of them found elsewhere in the universe, to date) and anti-matter (the same elements but with anti-protons in the nucleus and positrons instead of electrons circling around the nucleus),\n\nWhat are these Elements called?\n\nIn 1959 Tom Lehrer sang the following ditty to a Harvard audience (to the tune of Gilbert and Sullivan's I am the Very Model of a Modern Major General)\n\n``There's antimony, arsenic, aluminum, selenium, \nAnd hydrogen and oxygen and nitrogen and rhenium \nAnd nickel, neodymium, neptunium, germanium, \nAnd iron, americium, ruthenium, uranium, \nEuropium, zirconium, lutetium, vanadium \nAnd lanthanum and osmium and astatine and radium \nAnd gold, protactinium and indium and gallium (inhale) \nAnd iodine and thorium and thulium and thallium. \n\n``There's yttrium, ytterbium, actinium, rubidium \nAnd boron, gadolinium, niobium, iridium \nAnd strontium and silicon and silver and samarium, \nAnd bismuth, bromine, lithium, beryllium and barium.  \n\n``There's holmium and helium and hafnium and erbium \nAnd phosphorous and francium and fluorine and terbium \nAnd manganese and mercury, molybdinum, magnesium, \nDysprosium and scandium and cerium and cesium \nAnd lead, praseodymium, and platinum, plutonium, \nPaladium, promethium, potassium, polonium, and \nTantalum, technetium, titanium, tellurium, (inhale) \nAnd cadmium and calcium and chromium and curium. \n\n``There's sulfur, californium and fermium, berkelium \nAnd also mendelevium, einsteinium and nobelium \nAnd argon, krypton, neon, radon, xenon, zinc and rhodium \nAnd chlorine, carbon, cobalt, copper, \nTungsten, tin and sodium. \n\n``These are the only ones of which the news has come to Harvard, \nAnd there may be many others but they haven't been discovered.'' \n\n(a few of the 116 eg Seaborgium were discovered after 1959 and are therefore not in the song)\n\nFor a Flash animation of the song go to \nhttp://www.privatehand.com/flash/elements.html
195709
The only element that has only one electron is hydrogen.  Is high pressure, such as the surface of Jupiter, or extremely low temperatures, hydrogen forms a solid which has the properties of an alkali metal-it is an electron donor.
821309
Smallest is Hydrogen, largest would be, although it hasn't been created yet, element 121 also called Unbiunium according to IUPAC nomenclature. I say that because that is the largest element that would be able to be produced using current particle accelerators and colliders.
1116812
The paper cited below says "It is the rarest element with an amount of only 550 g. in the entire earth's crust,"\n\nThat's a little more than 18 atoms.
778176
Use the periodic table of the elements.  The "weights" are in grams per mol.  Just use algebra and solve for the number of mols.  Then you know how many atoms there are by the number of mols which is a definite number.
663846
It is lithium. Ever heard of lithium batteries? Titanium is a very light metal, but not as light as lithium. It does not occur freely in nature.\n\nIts atomic mass is 6.941 (2) g/mol
756517
Atoms have mass which can sometimes have volume and there are about 6.022x10^23 particles in a mole of an element. A mole of an element is the atomic mass in grams. Now, you can use all this and do some further research on the Internet and in books to write a nonfiction book on atoms and how the periodic table of the elements is set up.
546865
First, it seems to have only 2 isotopes.  \n\nYou need to take each mass and multiply by its percentage.  Then add the two resulting numbers together.  You then have the weighted average mass for the element, or average atomic mass.  This weighted average atomic mass is the one reported on the periodic table of elements.\n\n35 x 40%\n+\n37 x 60%
797180
Atomic mass depends on the element. It accounts for all isotopes and does a sort of weighted average, depending on how often the isotope occurs in nature.\nMass number depends on the isotope.\n\nFor example, atomic mass of hydrogen is 1.0079. The mass number of most hydrogen atoms is 1. Deuterium is an isotope with a neutron in its nucleus, so its mass number is 2. Tritium is an isotope with two neutrons, so its mass number is 3.
192086
Two or more elements combined make a compound. The smallest amount of an element is an atom. The smallest amount of a compound is a molecule. "Chemical" is a term with a wide range of interpretations. Depending on context, a chemical can be an element, a compound, a man-made substance, etc. See ref.
547549
From elementary chemistry it is known that the atomic structure of any element is made up of a positively charged nucleus surrounded by electrons revolving around it. An element’s atomic number indicates the number of positively charged protons in the nucleus. The atomic weight of an atom indicates how many protons and neutrons in the nucleus. To determine the number of neutrons in an atom, the atomic number is simply subtracted from the atomic weight.\n\nAtoms like to have a balanced electrical charge. Therefore, they usually have negatively charged electrons surrounding the nucleus in numbers equal to the number of protons. It is also known that electrons are present with different energies and it is convenient to consider these electrons surrounding the nucleus in energy “shells.” For example, magnesium, with an atomic number of 12, has two electrons in the inner shell, eight in the second shell and two in the outer shell.\n\nAll chemical bonds involve electrons. Atoms will stay close together if they have a shared interest in one or more electrons. Atoms are at their most stable when they have no partially-filled electron shells. If an atom has only a few electrons in a shell, it will tend to lose them to empty the shell. These elements are metals. When metal atoms bond, a metallic bond occurs. When an atom has a nearly full electron shell, it will try to find electrons from another atom so that it can fill its outer shell. These elements are usually described as nonmetals. The bond between two nonmetal atoms is usually a covalent bond. Where metal and nonmetal atom come together an ionic bond occurs.\n\nhttp://www.tech.farmingdale.edu/depts/met/met205/atomicbonds.html\n\nhttp://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm
573382
Magnesium is the 12th element (atomic number 12).\n\nCarbon is the 6th element, but has an atomic mass of 12.
879268
Zinc is by far the best element. I also like plutonium.  It's just fun to say. "Plutonium."
902490
Silicon's elemental number is 14, meaning it has 14 protons. If the atomic weight is 28, then subtracting 14 (the mass of the protons) gives you the solution, 14 neutrons.\n\nAtomic mass = mass of protons + mass of neutrons + a tiny bit of mass from electrons.\n\nProtons and neutrons have nearly the same mass, and electrons have hardly any mass at all.
44826
Copper is #29 on the period table (yes, 4th period), but notice it's average atomic mass is 63.55.  Since electrons weight practically nothing, that means the weight of the protons and neutrons is 63.55.  Since it is #29, it has 29 protons by definition.  So on average it has 63.55 - 29 = 34.55 neutrons.\n\nRemember that though an element has roughly the same number of neutrons as protons, each atom can have a different number of neutrons.  These are called "isotopes".  But on average, copper has 34.55, according to the periodic table I've cited below.