The atomic mass of an element is usually fractional because:a)Elements...
The atomic masses of most elements are fractional because they exist as a mixture of isotopes of different masses. Most elements occur as a mixture of isotopes of different masses. The fractional atomic masses arise because of this mixture. Average mass = total mass of all atoms /number of atoms.
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The atomic mass of an element is usually fractional because:a)Elements...
Explanation:
The atomic mass of an element is usually fractional because elements are a mixture of isotopes.
Isotopes:
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. These different isotopes have slightly different atomic masses. For example, carbon has three isotopes: carbon-12, carbon-13, and carbon-14. Carbon-12 is the most abundant isotope, followed by carbon-13 and carbon-14. Each isotope contributes to the overall atomic mass of carbon.
Weighted Average:
The atomic mass of an element is calculated as a weighted average of the masses of its isotopes. The average atomic mass takes into account the abundance of each isotope in nature. The atomic mass is expressed in atomic mass units (amu) and is usually a decimal number because it is a weighted average of the isotopes' masses.
Example:
To illustrate this concept, let's look at the atomic mass of chlorine. Chlorine has two isotopes: chlorine-35 and chlorine-37. Chlorine-35 is more abundant in nature, making up about 75% of chlorine atoms. Chlorine-37 is less abundant, making up about 25% of chlorine atoms. Therefore, the atomic mass of chlorine is calculated as a weighted average:
(0.75 x 35 amu) + (0.25 x 37 amu) = 35.5 amu
The atomic mass of chlorine is 35.5 amu, which is a fractional value due to the contribution of the two isotopes.
Conclusion:
In conclusion, the atomic mass of an element is usually fractional because it is a weighted average of the masses of its isotopes. The different isotopes have different abundances, which result in a fractional atomic mass.
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