what element on the periodic table has the mass of 68?
605534
TrueGentalman, Actually Such element DOES Exist.  Read on...\n\nErbuim has the atomic number of 68, but its Mass is not 68 amu.  It is actually 167.26 amu or 167.26g/mol.  Although it appears that no element has the exact mass of 68 amu in periodic table, Zinc having mass of 65.39 has a mass very close to 68.\n\nThe fact that Zinc has mass with a decimal suggests that it has isotopes and Zinc indeed has many isotopes.  \n\nThe TRUE answer to this question is Zinc-68.  It is a naturally occurring stable isotope of Zinc having atomic mass of exactly 68 amu.  \n\nI hope this helps.
948794
protons is the atomic number\nvalence electrons corresponds to this:\nGroup 1 (I) (alkali metals) :1\nGroup 2 (II) (alkaline earth metals) :2\nGroups 3-12 (transition metals) :1 or 2\nGroup 13 (III) (boron group) :3\nGroup 14 (IV) (carbon group) :4\nGroup 15 (V) (nitrogen group) :5\nGroup 17 (VII) (halogens) :7\nGroup 18 (VIII or 0) (noble gases) :8\n\n\nEvery element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons. It goes down the periodic table like that. At this time, the maximum number of electron orbitals or electron shells for any element is seven.
288114
The atomic number tells you how many protons there are in the nucleus, and that's what identifies the element.  Subtract that number from the atomic weight and you get the number of neutrons.  Uranium has 92 protons and 143 neutrons (U235) or 146 neutrons (U238).  The different weights are called isotopes.  In an electrically neutral atom the number of electrons is the same as the number of protons.  Strip a few electrons away you get an ion (an ionized atom).  It's the structure of the electrons that strongly influences the chemical properties of the element.
30888
I'm not really sure what you mean, but here's a good site to look at the periodic table.\n\nhttp://en.wikipedia.org/wiki/Periodic_table
853125
The atomic number of Aluminum is 13 (look at a periodic table). This means 13 protons and 13 electrons (since these are oppositely charged they have to balance each other.) To find the number of neutrons you subtract the number of protons from the atomic mass (the atomic mass is 27). So 27-13= 14 neutrons
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.
498169
Here you go: http://en.wikipedia.org/wiki/Periodic_table\n\nAhhh.. good old Wikipedia. :)
393625
mass # =#protons + # neutrons\nand # protons = # electrons in an electronically neutral atom.\nso you can therefore find the # nuetrons\n#neutrons=mass#-# protons
697898
pull out your periodic table and this becomes very easy.  elements have an oxidation # of 0.
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.
573382
Magnesium is the 12th element (atomic number 12).\n\nCarbon is the 6th element, but has an atomic mass of 12.
737340
Z = 13    A = 27    The chemical symbol is Al.\nThe sum of the superscripts on the left side of the arrow must equal the sum of the superscripts on the right side of the arrow.  The same is true for the subscripts.  Adding 4 + 26 = 30 for the superscripts on the left, so 27 must be the unknown mass number (A).  Adding 2 + 12 = 14 for the subscripts on the left, 13 must be the missing atomic number on the right (Z).  Z tells you the element, which is aluminum.
157964
1.8 log\n\n60 ppm\n\nCerium ranks 26th in natural abundance among the elements in the earth's crust.
150149
Francium has 87 protons.  This information is available on the Periodic Table of Elements, the atomic number (Z) of an element is the number of protons.
123587
Periodic Table is in order of increasing atomic no. so\n\n1st Step: find the placement of the element, in the present case it is on third place so no. of protons is three.\n\n2nd Step: In the Periodic Table, number of electron is always equal to number of protons so far three protons of Lithium there will be three electrons.\n\n3rd Step: Periodic Table also give atomic weights of the elements. Simply atomic weight is equal to sum of number of protons and nutroms.\n\n4th Step: Note the atomic weight of the element. Most of the elements in Periodic Table show atomic weights in fractions. In the case of Lithium it is 6.9 \n\n5th Step: Convert the fractional figure into nearest whole number. In case of Lithium it is 7\nNote:In the Periodic Table atomic weight is average of all isotopes (different atomic weights of same element). The nearest whole number refers to the most abundent  or the common atom (Isotop).\n\n6th Step: Subtract atomic number (protons) from atomic weight (neutron=proton), the difference is number of neutrons. In Lithium 7-3=4 so there are 4 neutrons
148855
Note that mass number is not the same thing as atomic mass; mass number is always a whole number, whereas atomic mass is always an average of the various isotopes of that element.  Lithium can have a mass number of 6, but it's more commonly 7, and its atomic mass is 6.941.
213411
Atomic Number 3\nhttp://www.jergym.hiedu.cz/~canovm/vyhledav/varianty/litva.gif