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What's the third most common element?

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Re: What's the third most common element?

#11

Post by natejenkins »

What caught my eye was the oscillation in the abundancy graph, there is a tendency for even atomic number elements to be more abundant than odd atomic number elements. Looking at the original Wikipedia article leads to the Oddo-Harkins rule http://en.wikipedia.org/wiki/Oddo%E2%80%93Harkins_rule. There is more discussion on the stability of even vs odd atomic number elements here: http://en.wikipedia.org/wiki/Even_and_odd_atomic_nuclei. From the latter link, roughly 60% of stable nuclei have an even number of protons and an even number of neutrons. Only 2% have an odd number of protons and an odd number of neutrons.

It would be nice if someone could explain any of the exceptions to the Oddo-Harkins rule, such as the dip at atomic number 44, Ruthenium.

Re: What's the third most common element?

#12

Post by sltkr »

maaaats wrote: post #7
gpvos wrote: post #4

Earlier quoted context omitted.

Please just upvote the post instead.

Please just downvote the comment instead. ;)

I think in cases where the original comment appears to be made in good faith, it's OK to explain what's wrong with it/what to do instead. That's how people learn.

(Obvious spam/flames/etc. should just be downvoted, ofcourse.)

Re: What's the third most common element?

#13

Post by lmm »

raverbashing wrote: post #10
ghubbard wrote: post #3

What's the third most common element (in the universe)? tl;dr: Oxygen But it's worth reading the article to learn why.

From what we can conclude that: water is very common (Of course, most likely not in liquid form)

No we can't. If it's not molecules, it's not water, and there's nothing here to indicate whether the hydrogen and oxygen are found bound together.

Re: What's the third most common element?

#15

Post by throwaway_yy2Di »

natejenkins wrote: post #11

What caught my eye was the oscillation in the abundancy graph, there is a tendency for even atomic number elements to be more abundant than odd atomic number elements. Looking at the original Wikipedia article leads to the Oddo-Harkins rule http://en.wikipedia.org/wiki/Oddo%E2%80%93Harkins_rule . There is more discussion on the stability of even vs odd atomic number elements here: http://en.wikipedia.org/wiki/Even_an…

I don't think that's ruthenium -- that graph has a gap at technetium (Z=43), which has no long-lived isotopes. The line actually joins Z=42 and Z=44.

(Might also be confusing that Sn (Z=50) is labelled at the wrong place (Z=48)).

edit: here's a modified version,

https://i.imgur.com/0iQ6vNX.png

Re: What's the third most common element?

#16

Post by raverbashing »

lmm wrote: post #13
raverbashing wrote: post #10

Earlier quoted context omitted.

From what we can conclude that: water is very common (Of course, most likely not in liquid form)

No we can't. If it's not molecules, it's not water, and there's nothing here to indicate whether the hydrogen and oxygen are found bound together.

https://en.wikipedia.org/wiki/Water#In_the_universe

While water will break down at high temperatures I would find it surprising that 1st and 3rd most common elements in the whole universe, that readily combine to form water would not result in substantial amounts of water.

It's probably like saying we shouldn't find H2 because "nothing says they are found bound together"

Re: What's the third most common element?

#17

Post by gpvos »

evantahler wrote: post #9

Surprise?

Well, yeah. I thought it was carbon, and I thought it was way ahead of the others. But instead there are actually a bunch of elements vying pretty closely for third position: oxygen, carbon, neon, nitrogen, magnesium, silicium, iron, sulphur. (Although one should keep in mind that the graph is logarithmic.)

Note that the graph actually shows the estimated abundance of elements in the solar system (found that on Wikipedia), not the universe or the Milky Way. The article misrepresents that!

Re: What's the third most common element?

#18

Post by gpvos »

raverbashing wrote: post #16
lmm wrote: post #13

Earlier quoted context omitted.

No we can't. If it's not molecules, it's not water, and there's nothing here to indicate whether the hydrogen and oxygen are found bound together.

https://en.wikipedia.org/wiki/Water#In_the_universe While water will break down at high temperatures I would find it surprising that 1st and 3rd most common elements in the whole universe, that readily combine to form water would not result in substantial amounts of water. It's probably like saying we shouldn't find H2 because "nothing says they are found bound together"

Still can't conclude it from just the data presented here.

Re: What's the third most common element?

#19

Post by gpvos »

ghubbard wrote: post #3

What's the third most common element (in the universe)? tl;dr: Oxygen But it's worth reading the article to learn why.

Note that the very interesting graph near the end of the article actually displays element abundance in the solar system, not in the universe. (Found that out when looking it up in Wikipedia.) The article misrepresents this!

Re: What's the third most common element?

#20

Post by raverbashing »

gpvos wrote: post #18
raverbashing wrote: post #16

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/Water#In_the_universe While water will break down at high temperatures I would find it surprising that 1st and 3rd most common elements in the whole universe, that readily combine to form water would not result in substantial amounts of water. It's probably like saying we shouldn't find H2 because "nothing says they are found bound together"

Still can't conclude it from just the data presented here.

You have to explain more than that
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