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This is because of the existence of isotopes. What's an isotope? It's an element that has a specific number of neutrons. I'll give an example. Carbon has 6 Neutrons, 6 Protons, 6 Electrons.
That's the most common form of Carbon. But 1% of all Carbon is an isotope that has 1 extra Neutron. So it weighs 1 more, also. So this isotope weighs 13 instead of 12. We call it Carbon 13, or 13C.
There's also a 14C and so on....but in far smaller amounts.
So anyhow, since we have 99% Carbon weighing 12 and 1% Carbon weighing 13, what weight do we put on our Periodic Table?
Well, I guess we could put the most common.
But what about Bromine? That has 2 major isotopes. One weighs 79 and the other 81, they are 51% and 49% (very roughly) abundant respectively.
That's almost an exact split...it'd be pretty ridiculous to only put the weight of one.
So instead we say it's weight is 79.9...which is it's weight averaged over all of it's isotopes, with respect to their abundance.
It doesn't seem right to average it on an atom-to-atom basis. But if I'm weighing 2grams of my sample, there are HUGE numbers of molecules there. And the only way I can do an accurate calculation is to know an averaged mass, because my sample WILL contain all of the isotopes.
If I calculate for only 1 isotopic weight, my calculations will be wrong. That's why we average them.
Harvey Schowalter
Eloise Upton
This is because of the existence of isotopes. What's an isotope? It's an element that has a specific number of neutrons. I'll give an example. Carbon has 6 Neutrons, 6 Protons, 6 Electrons.
That's the most common form of Carbon. But 1% of all Carbon is an isotope that has 1 extra Neutron. So it weighs 1 more, also. So this isotope weighs 13 instead of 12. We call it Carbon 13, or 13C.
There's also a 14C and so on....but in far smaller amounts.
So anyhow, since we have 99% Carbon weighing 12 and 1% Carbon weighing 13, what weight do we put on our Periodic Table?
Well, I guess we could put the most common.
But what about Bromine? That has 2 major isotopes. One weighs 79 and the other 81, they are 51% and 49% (very roughly) abundant respectively.
That's almost an exact split...it'd be pretty ridiculous to only put the weight of one.
So instead we say it's weight is 79.9...which is it's weight averaged over all of it's isotopes, with respect to their abundance.
It doesn't seem right to average it on an atom-to-atom basis. But if I'm weighing 2grams of my sample, there are HUGE numbers of molecules there. And the only way I can do an accurate calculation is to know an averaged mass, because my sample WILL contain all of the isotopes.
If I calculate for only 1 isotopic weight, my calculations will be wrong. That's why we average them.
The Atomic Mass of an element is a weighted average because it takes into account the abundance of each isotope of that element. Isotopes are atoms of the same element with different mass numbers due to varying numbers of neutrons. The atomic mass is calculated by multiplying the mass of each isotope by its relative abundance and summing up these values to give an average.
Wiki User
∙ 14y agoThis is because of the existence of isotopes. What's an isotope? It's an element that has a specific number of neutrons. I'll give an example. Carbon has 6 Neutrons, 6 Protons, 6 Electrons.
That's the most common form of Carbon. But 1% of all Carbon is an isotope that has 1 extra Neutron. So it weighs 1 more, also. So this isotope weighs 13 instead of 12. We call it Carbon 13, or 13C.
There's also a 14C and so on....but in far smaller amounts.
So anyhow, since we have 99% Carbon weighing 12 and 1% Carbon weighing 13, what weight do we put on our Periodic Table?
Well, I guess we could put the most common.
But what about Bromine? That has 2 major isotopes. One weighs 79 and the other 81, they are 51% and 49% (very roughly) abundant respectively.
That's almost an exact split...it'd be pretty ridiculous to only put the weight of one.
So instead we say it's weight is 79.9...which is it's weight averaged over all of it's isotopes, with respect to their abundance.
It doesn't seem right to average it on an atom-to-atom basis. But if I'm weighing 2grams of my sample, there are HUGE numbers of molecules there. And the only way I can do an accurate calculation is to know an averaged mass, because my sample WILL contain all of the isotopes.
If I calculate for only 1 isotopic weight, my calculations will be wrong. That's why we average them.
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What is the average atomic mass compared to atomic mass?
The average atomic mass is a weighted average of the masses of all isotopes of an element, taking into account their abundance. The atomic mass listed on the periodic table is the weighted average of all naturally occurring isotopes of the element. So, they are essentially the same thing, with the average atomic mass being a more specific term.
Which best describes the definition for the atomic mass of an element?
The atomic mass of an element is the average mass of an element's isotopes, weighted by their natural abundance. It is expressed in atomic mass units (u) and is often close to the mass number of the most abundant isotope of the element.
How the atomic mass of an element is affected by the distribution of its isotopes in nature?
The atomic mass of an element is the average of its isotopes, weighted by abundance in nature.
What is the difference between average atomic mass and atomic mass?
Average atomic mass is the weighted average mass of all the isotopes of an element, taking into account their natural abundances. Atomic mass refers to the mass of a single atom of a specific isotope of an element.
Which best describes the definition of the atomic mass of an element?
it is the weighted average of the masses of an element's isotopes.
The average atomic mass of an element is the average of the atomic masses of its?
The average atomic mass of an element is the average of the atomic masses of its isotopes (that is a weighted average). You have to take into account the abundance of each isotope when they do your averaging.
An average of the masses of all the naturallly occurring isotopes of an element?
The weighted average for all isotopes that occur in nature for an element is its atomic weight listed on the Periodic Table of the elements.
What is the weighted average of the atomic masses of an element's naturally occurring isotopes is called the?
The weighted average of the atomic masses of an element's naturally occurring isotopes is called the atomic mass. This value takes into account the abundance of each isotope in nature when calculating the overall average atomic mass of the element.
How is the atomic mass of an element affected by the distribution of its isotopes in nature?
The atomic mass of an element is the average of its isotopes, weighted by abundance in nature.
How the atomic mass of an element is affected by the distribution of its isotopes in nature?
The atomic mass of an element is the average of its isotopes, weighted by abundance in nature.
What is the average atomic mass compared to atomic mass?
The average atomic mass is a weighted average of the masses of all isotopes of an element, taking into account their abundance. The atomic mass listed on the periodic table is the weighted average of all naturally occurring isotopes of the element. So, they are essentially the same thing, with the average atomic mass being a more specific term.
What is the difference between average atomic mass and atomic mass?
Average atomic mass is the weighted average mass of all the isotopes of an element, taking into account their natural abundances. Atomic mass refers to the mass of a single atom of a specific isotope of an element.
How do the decimal places on the atomic masses of elements realate to isotopes?
The atomic mass of an element is the weighted average of masses of the isotopes of the element, weighted in proportion to their abundance.
Which best describes the definition of the atomic mass of an element?
it is the weighted average of the masses of an element's isotopes.
Which best describes the definition for the atomic mass of an element?
The atomic mass of an element is the average mass of an element's isotopes, weighted by their natural abundance. It is expressed in atomic mass units (u) and is often close to the mass number of the most abundant isotope of the element.
The weighted average of the masses of all the naturally occurring isotopes of an element is the what?
Atomic weight or atomic mass used in stoichiometric calculations.
Weighted average atomic mass?
What is weighted average atomic number
