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There are different isotopes of the element.
Isotopes are atoms of an element that have different amounts of protons, so the isotopes with more protons weigh more because there is more mass in the atom.
Some isotopes are more common than others, and the atomic mass is a weighted AVERAGE of all the isotopes of that element. On most elements there is a large difference between the most common and lesser common isotopes, but chlorine has 2 isotopes that are very close. So the average ends up between the two numbers.
The actual weight of 1 atom will never be something.5 because protons and neutrons weigh 1amu and electrons weigh 0. But in most cases the sample of a chemical you use will be a mixture of the isotopes, so the .5 weight will be correct.
Wiki User
∙ 14y ago
The Atomic Mass of chlorine is a weighted average of the masses of all its naturally occurring isotopes, taking into account their abundance. Chlorine has two main isotopes, chlorine-35 (with an atomic mass of approximately 34.97) and chlorine-37 (with an atomic mass of approximately 36.97). The 0.5 difference in the atomic mass comes from the relative abundance of these isotopes in nature.
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8. On most periodic tables a single atomic mass is listed instead of the mass numbers for all the stable isotopes. How is this mass related to the different isotopes?
In a normal periodic table, the molar mass of a given element, is made up of multiplying the mass of a given isotope of that element, with the abundance of that given isotope in percent. For example, Say for the element X, you know that it has two isotopes, X12 and X13. X12 has a molar mass of 12 g/mol, and you know that of all the X molecules in the world, X12 is found 95% of the time, X13 has a molar mass of 13g/mol, yet its abundence is only 5%. Therefore average molar mass for element X is calculated as such, (12 * .95)+(13*.05) = 12.05 g/mol. hope that helps.
How much energy is released if a sample losses 05 kg mass through readioactive decay?
4.5 * 10^15 J
When was the first atomic explosion?
There has never been an atomic detonation to date in mexican territory. Since the country sponsored and signed the Treaty of Tlatelolco wich objective is to ban any nuclear based weapon in Latin America, it is still unlikely that Mexico would develop or test nuclear weapons.
How many points in a gram?
There are 15.432 grains in one gram224 grains=1 dwt / 1 { pennyweight } =.05 troy ounce / 1 gram=.643 pennyweight / 1 grain = 0.0648 grams / 4 grains = 1 carat / 15.432 grains = 1 Gram
How many kilograms in 500mg?
0,0005 kg
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