Most abundant elements on earth?

In summary: Earth, I think the answer is pretty self-explanatory. Obviously, we humans are interested in what is around us and what makes us who we are. So, when looking at the Earth as a whole and considering all of the elements we can measure, we are drawn to measuring elements by weight because it is a metric that is both easily interpreted and broadly applicable. To try to calculate the abundance of elements in any other way would be much more time consuming and likely inconclusive. Thank you for your input!
  • #1
Lapidus
344
11
All sources I have found on the web give the abundance of the elements on Earth measured by weight. By that oxygen is number one or iron, depending on where you look.

But when counting just the number of atoms wouldn't that make hydrogen number one?

thanks
 
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  • #2
Lapidus said:
All sources I have found on the web give the abundance of the elements on Earth measured by weight. By that oxygen is number one or iron, depending on where you look.

But when counting just the number of atoms wouldn't that make hydrogen number one?

thanks

I think you need to be clear here. Are you talking about abundance for the entire Earth or just the crust, or what? In the crust, hydrogen is relatively rare, whereas silicon is as common as sand at the shore.
 
  • #3
Thanks for replying. I meant the entire earth. Why would I ask for the crust, what is so special about it?

And is hydrogen mainly just in the water, but rare in the inner earth? Does oxygen in the air, in the water and in the crust outnumber the double number of hydrogen atoms in water?
 
  • #4
Lapidus said:
Thanks for replying. I meant the entire earth. Why would I ask for the crust, what is so special about it?

And is hydrogen mainly just in the water, but rare in the inner earth? Does oxygen in the air, in the water and in the crust outnumber the double number of hydrogen atoms in water?

Why don't you try some calculations? For example, how many oxygen atoms are there in the Earth's mantle? How does this compare to the number of hydrogen atoms in the Earth's oceans?
 
  • #5
Lapidus said:
Thanks for replying. I meant the entire earth. Why would I ask for the crust, what is so special about it?

In case you haven't noticed, it's where humans live and spend most of their time while alive. It's also quite handy for doing experiments, like finding out the relative abundance of the elements. You also have to look at published tables of elemental abundances on earth, because they usually contain disclaimers like 'for the Earth's crust.'

We can analyze lava flows to determine the composition of the upper mantle, and we can theorize what the core is composed of and estimate its size based on gravitational measurements.

And is hydrogen mainly just in the water, but rare in the inner earth? Does oxygen in the air, in the water and in the crust outnumber the double number of hydrogen atoms in water?

What phyzguy suggested. A good candidate for a 'back of the envelope' calculation.
 
  • #6
Thanks for replying. I meant the entire earth. Why would I ask for the crust, what is so special about it?

because its where most of the elements are found


D
 
  • #7
davenn said:
because its where most of the elements are found
D

What do you mean by that? The Earth's crust is less than 1% of the Earth's volume.
 
  • #8
phyzguy said:
What do you mean by that? The Earth's crust is less than 1% of the Earth's volume.

I think he means that practically all of the elements we physically find are located in the crust since we can't get any from anywhere else in the Earth.
 
  • #9
Drakkith said:
I think he means that practically all of the elements we physically find are located in the crust since we can't get any from anywhere else in the Earth.

so true :wink: at least someone understood
and also consider you will most likely find most of the lightest element are in the crust and lithosphere rather than in the mantle or deeper

Dave

edit ...

http://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth's_crust[/PLAIN] [Broken]

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/elabund.html

http://www.periodictable.com/Properties/A/CrustAbundance.an.log.html
 
Last edited by a moderator:
  • #10
You need to consider how aggressive your rhetorical question sounds about why you would ask such and such. Why would you ask about number of atoms? Same reason you'd ask about the crust, I suppose: because you are interested. Based on what we know, the Earth's core is mostly iron. But we haven't been down there to check. So, the Earth's composition is quite speculative. Obviously, if Fe and O are approximately equally abundant by weight, then by number, O wins hands down. Hydrogen would have to occur in high concentrations to be the most numerous...but then again I don't think we can rule it out with any certainty (as water and hydrates). As far as your comment about the Crust "only" being a fraction of the total, yeah we exist on what many have called scum floating on the mantle. But then again who says quantity is more important than quality?
 
  • #11
Hydrogen in the core: practically none
Hydrogen in the mantle: minor role in a few hydrous minerals
Oxygen in mantle: abundant, since it - with silicon - forms SiO4 tetrahedra, the backbone of the silicates of which the mantle is largely composed.
The crust: irrelevant because of its low volume.

Oh, and as to why people may have thought you meant the crust, you asked about elements on the Earth, not in the Earth.
 
  • #12
davenn said:
because its where most of the elements are found

D
phyzguy said:
What do you mean by that? The Earth's crust is less than 1% of the Earth's volume.
Drakkith said:
I think he means that practically all of the elements we physically find are located in the crust since we can't get any from anywhere else in the Earth.
Agreed. Note davenn's choice of words: where most elements are found is not the same as where most elements are located.
 
  • #13
Lapidus said:
All sources I have found on the web give the abundance of the elements on Earth measured by weight. By that oxygen is number one or iron, depending on where you look.

But when counting just the number of atoms wouldn't that make hydrogen number one?

thanks

If you divide whatever abundance by weight numbers you have, crust core or atmosphere, by the atomic weights, you get the abundance by numbers. This will enable you to decide which is the most abundant element by number. ;-)
 

What are the most abundant elements on Earth?

The most abundant elements on Earth are oxygen, silicon, aluminum, iron, and calcium.

How do scientists determine the abundance of elements on Earth?

Scientists determine the abundance of elements on Earth through various methods such as analyzing rocks and minerals, studying the Earth's crust, and conducting experiments.

Why are oxygen and silicon the most abundant elements on Earth?

Oxygen and silicon are the most abundant elements on Earth because they are key components of the Earth's crust and make up a large portion of rocks and minerals.

Are the most abundant elements on Earth the same as the most abundant elements in the universe?

No, the abundance of elements on Earth is different from the abundance in the universe. Hydrogen and helium are the most abundant elements in the universe, while oxygen and silicon are the most abundant on Earth.

How does the abundance of elements on Earth affect life on the planet?

The abundance of elements on Earth plays a crucial role in sustaining life. For example, oxygen is essential for respiration, and calcium is necessary for building strong bones and teeth.

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