Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: joeweller on 10/06/2016 14:00:42

Title: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: joeweller on 10/06/2016 14:00:42

(https://1.bp.blogspot.com/-jlYzWaYImzE/V1q379C1NvI/AAAAAAAABKI/hkSRe5_wQT8Q1sxijNUoQiIMkUqfIr-IQCLcB/s640/tLzEwgF.jpg)

This is a Periodic Table by Abundance. It is an old version; is it still accurate?

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: chiralSPO on 10/06/2016 16:40:09

It looks like this is reporting the abundance on Earth. It looks about right except for Fr and Pt, which should both be much smaller.

Compare to: https://upload.wikimedia.org/wikipedia/commons/thumb/0/09/Elemental_abundances.svg/300px-Elemental_abundances.svg.png and https://www.uwgb.edu/dutchs/Graphics-Geol/geochem/ptabccr.gif

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: chris on 10/06/2016 18:27:31

Is there really that much oxygen? I thought hydrogen was much more abundant...?

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: joeweller on 10/06/2016 18:49:22

Quote from: chris on 10/06/2016 18:27:31

Is there really that much oxygen? I thought hydrogen was much more abundant...?

well I don't remeber where I saw this but I think that hydrogen is more abundant in space

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: chiralSPO on 10/06/2016 20:34:32

I think it's a question of whether we are talking about abundance by mass or by number of atoms. In Space, it's almost entirely hydrogen, with some helium, and a smattering of other elements, so this must be showing the abundance on Earth.

There is a LOT of oxygen on earth. Silica (SiO₂) silicates (SiO₄^4–) carbonates (CO₃^2–), sulfates (SO₄^2–) phosphates (PO₄^3–) etc. are a significant proportion of the minerals on Earth.

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: evan_au on 11/06/2016 02:13:57

Quote from: Chris

I thought hydrogen was much more abundant...?

Of course, if you were measuring the Solar System, it would be mostly Hydrogen, a bit of Helium, and not very much of anything else - primarily due to the Sun and Jupiter.

Another measure is by volume. If you are looking at the surface of the Earth:

• In water, the Oxygen is much larger than the hydrogen (and much of the earth's hydrogen is bound up in water and hydrocarbons/carbohydrates).
  
• Oxygen often forms an O^2- ion, and it swells up considerably compared to neutral oxygen atoms.
  
• If I remember my geology classes, in silicates, the Oxygen atoms take up a considerable volume, with the silicon atoms nestled in-between.
  

If you are looking at the core of the Earth, you would find mostly Iron and Nickel, plus elements which are soluble in these metals.

Title: Re: Is this version of the periodic table, plotting elements by abundance, accurate?
Post by: Bored chemist on 11/06/2016 11:48:16

Broadly, the radioactive ones are wrong. far too much Pa, Ra, Fr, Po, At and Rn etc compared to , eg U.