From: Geoff Ruth (gruth@leadershiphigh.org)
Date: Mon Nov 29 2004 - 07:19:29 PST
Message-Id: <p06110401bdd0eb5788db@[192.168.123.175]> Date: Mon, 29 Nov 2004 07:19:29 -0800 From: Geoff Ruth <gruth@leadershiphigh.org> Subject: Re: pinhole Pinhole: astatine? real names of the higher than 109?
Sue,
Webelements.com classifies astatine as a metalloid, but some other
sources I've looked at classify it as a nonmetal.
Maybe the problem is that it's too unstable to actually do a lot of
tests on it -- the longest-lived isotope of astatine has a half-life
of 8.3 hours. Moreover, according to webelements again, the largest
amount it can be created in is 0.001 mg. Given this short half-life
and low available amount, perhaps it's hard to get any accurate
information about its conductivity, sheen, or electron bonding
patterns.
Any elements passed uranium are not naturally occurring and can only
be synthesized in nuclear reactions. Anything passed bismuth has no
stable (ie, non-radioactive) isotopes. There are in fact names for
109-111: look at http://www.webelements.com/. Here's an article about
how the IUPAC names elements:
http://www.worldwidewords.org/articles/unnil.htm.
On a broader note, I'm not sure that it actually is important to try
to classify very unstable elements into the nonmetal-metal-metalloid
categories. This distinction is most useful for figuring out how
atoms bond with one another and interact with one another, but this
isn't really what unstable elements do, or at least are studied for.
(I'm not arguing that this distinction isn't useful for things like
uranium, where the U does make compounds, but rather for really
unstable things like At.) Although classifying everything on the
periodic table is useful for seeing the overall periodic table
patterns, it also seems to obscure what is unique about unstable
elements. This is just my opinion.
- Geoff
>Hi Pinholers,
>
>Please assist if you can. This is regarding the classification of Astatine (#
>85 on the periodic table), is it a metalloid or a nonmetal ...? On a Holt
>Chart it is categorized as a nonmetal and on a student's science chart of the
>periodic table which he purchased from a science store, it shows astatine as a
>metalloid. Which is most correct ... or is it one of those that can go either
>way?
>
>The other question is regarding the most current names for elements 110 and
>higher. Are they found in nature? Do they have names other than
>unnilinium, etc
>... and are their atomic masses stable or what? Any info is greatly
>appreciated. Thank you. The chart that will be used for the 8th
>grade science test
>shows only up to 109 on the periodic table so I was curious.
>
>Thanks for the insights.
>
>Take care and Happy Holidays,
>Sue Pritchard
>
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