what is the atomic mass of magnesium/??
462911
relative atomic mass of magnesium (Mg) is 24.5
578092
Name of Element : Thallium \nSymbol of Element : Tl \nAtomic Number of Thallium : 81 \nAtomic Mass: 204.3833 amu \nMelting Point: 303.5 °C - 576.65 °K\nBoiling Point: 1457.0 °C - 1730.15 °K\nNumber of Protons/Electrons in Thallium : 81\nNumber of Neutrons in Thallium : 123 \nCrystal Structure: Hexagonal \nDensity @ 293 K: 11.85 g/cm3\nColor of Thallium : bluish-gray
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.
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%
832813
atomic mass is, well the mass. also the number of protons + neutrons. Atomic number is the number of protons, which is also the number of electrons
715558
OK, but you need to look up atomic weights or calculate molar mass.\n\n   Grams = Moles x molar mass  OR  moles x atomic mass\n\n    Moles = Grams/(molar mass) OR Grams/(atomic mass)
3987
Magnesium is listed in the periodic table as having the following properties:\nSymbol: Mg\nAtomic number: 12\nAtomic weight: 24.3050\n\nThe atomic number is the same as the number of protons. The atomic weight is the number of protons plus the average number of neutrons found in magnesium nuclei in nature (with a small correction mostly due to the fact that the binding energy of the nucleus is included in its mass via E=mc^2). Most naturally occurring Magnesium atoms (about 80% of them) have 12 neutrons, while 10% have 13 neutrons and 10% have 14 neutrons. The different numbers of neutrons indicate the different isotopes of Magnesium. The chemical properties of Magnesium depend (nearly) entirely on the electrons, and therefore depend on how many protons there are, and not how many neutrons; add extra neutrons and it's still "Magnesium", but it may weigh more. A handbook of chemistry and physics lists all isotopes with between 8 and 16 neutrons. All except the three naturally occurring isotopes are radioactive and decay to other nuclei. \nhttp://van.hep.uiuc.edu/van/qa/section/Everything_Else/The_Elements/20021026080623.htm \nThese links will help you understand the concepts more nicely.\nhttp://www.crocodile-clips.com/absorb/AC4/sample/LR303.html\nhttp://van.hep.uiuc.edu/van/qa/section/New_and_Exciting_Physics/Inside_the_Atom/982893827.htm
47846
Look up the atomic mass (sometimes called atomic weight) on the periodic table, and subtract the atomic number from it.  The atomic mass is (practically) equal to the total number of protons and neutrons, and the atomic number is equal to the number of protons.  When you subtract atomic number from atomic mass your subtracting the number of protons from the total number of protons and neutrons, which leaves you with just neutrons.
752020
A: 53\nB: Approx. 127 AMU\nC:  Atomic Number\n\nThe Element is Iodine by the way.
799181
The atomic mass of nitrogen is 14.00674 grams/mole and the atomic mass of calcium is 40.078 grams/mole.  At a level of accuracy of  four significant figures, the masses you have been given correspond to the mass of one mole of each of these elements.  Therefore, there is one mole of nitrogen atoms in 14.01 gms of N and one mole of calcium atoms in 40.08 gms of Ca.\n\nOne mole of atoms  = 6.022 * 10^23 atoms.
1138448
Look on a periodic table.\n\nIt should be listed below the atomic number as a decimal value.  The mass number is an average mass (in atomic mass units) of an element, based on different isotopes.  It equals the number of protons + the number of neutrons in the nucleus.
747425
I suppose mass is a fairly easily measured value. Compared to finding the number of atoms, it's easier to just stick a sample on a scale/balance and weigh it.\n\nAnd the masses provided on the periodic table are weighted averages of the different isotopes found in nature.
702947
The atomic weight is the mass in grams per mole (atomic mass of iron = 55.845).\n\nA mole is 6.02 x 10^23 atoms, therefore the mass of 500 atoms would be:\n\n500/(6.02x10^23) x 55.845 = 4.64 x 10^-20 grams.\n\nNotice that's 10 to the -20 power.
850100
I'll do one for you and then you can try the rest.\n\nMagnesium has 12 electrons, so follow your filling order. Each s orbital holds to electrons and each p orbital holds 6, so its:\n\n1s2 2s2 2p6 3s2\n\nIt has 2 electrons in its outer shell so to have a full outer shell it will lose 2 therefore the common ion It forms is Mg2+
482427
The "atomic" number refers to the place in the periodic table which corresponds directly (is equal to) the number of protons. The mass number is a weighted average involving commonly found isotopes.
210049
None of these particles. The mass of the proton and neutron are approximately 1 AMU, and the mass of an electron is approximately 1/1840 of that. So the electron mass is approximately 0.00054 AMU, not 0.000006 AMU .
843112
Do a search for the isotopes of gold.  The list should give you each of the isotopes with its "mass number" (there are about 35 isotopes beginning with Au-172 and going through Au-205. ) The mass number is the total number of protons + neutrons.  Since gold is element #79 all of its isotopes have 79 protons so just subtract 79 from the mass numbers to get the neutrons.  Assuming we are talking about neutral gold atoms, the electrons = protons = 79.