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Non Life Sciences => Chemistry => Topic started by: taregg on 16/01/2012 14:57:49

Title: Which is stronger, lithium and francium?
Post by: taregg on 16/01/2012 14:57:49

some say lithium is stronger than francium  and some say francium ....so what is  correct?

Title: Re: Which is stronger, lithium and francium?
Post by: chris on 16/01/2012 19:13:50

What do you mean by strength? If it is oxygen affinity that you are referring to, francium is at the bottom of group 1 and hence has an extremely high affinity for oxygen, or anything that wants to relieve it of its outermost electron. But if it's sheer mettalurgical strength that you are referring to, that's something quite different.

Chris

Title: Re: Which is stronger, lithium and francium?
Post by: CliffordK on 16/01/2012 19:41:35

Often people are concerned with density, or strength to weight ratio.

While not a perfect relationship, the elements with fewer protons/neutrons typically will have a lower density. 

And, thus, I would expect many measurements to show Lithium to have a better strength to weight ratio.

NASA actually used Lithium in Space Shuttle Fuel Tank Alloys.

Title: Re: Which is stronger, lithium and francium?
Post by: taregg on 17/01/2012 16:20:46

 can i have more answer...........plz

Title: Re: Which is stronger, lithium and francium?
Post by: CliffordK on 18/01/2012 04:00:28

Keep in mind that all isotopes of Francium (http://en.wikipedia.org/wiki/Isotopes_of_francium) are radioactive.

The longest halflife of Francium is about 20 minutes for ²¹²Fr.  It decays into a mix of Radon Gas, as well as Astatine, and continues down a lengthy decay chain.

So, even if you start with pure Francium, quickly you will have a big mix of stuff, including a portion of it being a noble gas (for a short period of time).