Element mass number

Element Mass number Percent Element Mass number Percent... 

It s Saturday night. The air is charged with possibility. Living in the moment, you peruse your personal copy of the periodic table. What s this You notice the numbers that appear below the atomic symbols appear to be related to the elements mass numbers — but they re not nice whole numbers. What could it all mean ... 

Element Mass number Mass (Da)fl Abundance (atom%)A Element Mass number Mass (Da)° Abundance (atom%)i... 

I Atomic mass and mass number are not the same. Atomic mass refers to the naturally occurring mixture of isotopes mass number refers to an individual isotope. Atomic mass is an average and is never an exact integer mass number is a sum (of the number of protons plus the number of neutrons) and is always an integer. Except for the artificial elements, mass numbers are not given in the periodic table. 

Atomic number Z Element Mass number A Half-life... 

Note that these subscript numbers give no new information. They simply indicate the atomic number of a particular element. On the other hand, mass numbers provide information that specifies particular atoms of an element. Mass numbers are written on the upper left side of the symbol. The following are the symbols of stable atoms of the first five elements written with mass numbers ... 

This Web site provides information on every element in the periodic table of elements. Click on any square in on the table and information on the element—mass, number, atomic structure, and more—will appear, along with additional links to information. 

Laboratory processes have now extended the radioactive element mass numbers beyond 238 to about 280. Each element from atomic numbers 1 to 110 is known to have at least one radioactive isotope. As of December 2001, about 3286 isotopes and isomers were thought to be known and recognized. Many stable and radioactive isotopes are now produced and distributed by the Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A., to customers licensed by the U.S. Department of Energy. 

Element Mass number Element Mass number Element Mass number... 

Element Mass Number Atomic Number of Isotope Number of Neutrons in Nucleus Isotope Symbol... 

Atomic no. and element Mass numbers of isotopes bombarded Half-life periods of radioactive products Nature of radiations emitted... 

Element Mass number Atomic mass Difference Natural abundance... 

Gamma emitter 1 0/y 0 Stable + nucleus of the same element Mass number same Atomic number same... 

Element Mass number Crystal structure TraCC) g (g/cm )... 

For each of the elements, mass number and atomic number are given based on the following convention The mass number A is given as a left-hand superscript,... 

The symbol is used to identify a nucleus, where Z is the chemical symbol of a given element. Mass number A defines the mass of a nucleus. Thus, there are 92 protons and 143 neutrons in the uranium nucleus 092. The number of nucleons Z is often omitted because the relevant information is contained in its chemical symbol. Thus, is the usual symbol. In the text below, a proton mass is marked by ntp. Mass can be measured in kilograms ( ip=1673X10 kg), or can be denominated in atomic units of mass (1 a.m.u. = 1.66X10 kg). It is sometimes also expressed in eneigy units ( ip=938.2 MeV). 

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