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Halogens

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Susannah Dingley
575900.  Sun Jun 28, 2009 4:15 pm Reply with quote

The halogens are chemical elements belonging to group 17 (formerly group VII) of the periodic table.



The name halogen is Greek for “salt producer”.

 
Posital
576002.  Mon Jun 29, 2009 1:08 am Reply with quote

Highly reactive: fluorine, (F); chlorine, (Cl); bromine, (Br); iodine, (I); and astatine, (At) - and possibly element 117.

 
Efros
576399.  Mon Jun 29, 2009 3:19 pm Reply with quote

Only group in the periodic table that has members in all three common states of matter at room temperature and pressure.

 
Posital
576501.  Mon Jun 29, 2009 6:07 pm Reply with quote

Efros wrote:
Only group in the periodic table that has members in all three common states of matter at room temperature and pressure.
I thought this was interesting and then found Caesium and Francium are liquid at room temp (and possibly Rb).
Having said that, their melting points are listed as 28C.

 
Efros
576504.  Mon Jun 29, 2009 6:14 pm Reply with quote

Hydrogen isn't a member of the alkali metals group, so there are no gases in group 1.

 
suze
576507.  Mon Jun 29, 2009 6:18 pm Reply with quote

Rubidium melts at 39°C, so can't really be considered to be a liquid at room temperature.

I'll just about give you caesium though - room temperature right here right now is probably not far away from 28°C.

When I was in school, we were taught that hydrogen was a member of Group I. Have things changed in the last 25 years?

 
Posital
576512.  Mon Jun 29, 2009 6:38 pm Reply with quote

It may not normally act like an alkali metal - but is always listed in group 1.

Although, have another look at 5,000,000 atmospheres pressure - where H might become a metallic superconducting superfluid.

Perhaps you'd invite Hydrogen to join the Halogen club?

 
Efros
576525.  Mon Jun 29, 2009 6:55 pm Reply with quote

Generally H is given its own ickle group all by itself, pretty much because it don't fit. If you look at a properly drawn periodic table H is usually separated from the alkali metals. I always tell my students that chemistry is full of rules which as soon as I explain them I will immediately show how chemistry breaks 'em. So even if we include H as a Group 1 alkali metal we still have the problem of a liquid member (ooer missus). Fr is the best bet but good luck finding enough of that to measure its melting point, the others have melting points that could only be taken as room temperature in bloody hot rooms.

 
zomgmouse
576531.  Mon Jun 29, 2009 7:13 pm Reply with quote

Group 1 metals are not for studying, the are for throwing into water and watching pretty explosions.

 
Efros
576535.  Mon Jun 29, 2009 7:18 pm Reply with quote

you mean like this one

http://www.youtube.com/watch?v=QSZ-3wScePM


I wish we could embed video here.

 
npower1
644491.  Wed Dec 09, 2009 12:30 am Reply with quote

Having just paid for a halogen oven, but not yet used, I'm hoping that efros's youtube reference will not be part of my experience.

 
npower1
645810.  Sun Dec 13, 2009 11:31 am Reply with quote

I've started experimenting with my new halogen oven. Bacon, gammon steak, and sausages have turned out well.

One tip is that when the light is on it is very difficult to judge just how browned the sausages are. I assume this is because of the brightness.

One other tip is this youtube short (1:12).

 
bobwilson
646019.  Sun Dec 13, 2009 9:27 pm Reply with quote

Efros wrote:
you mean like this one

http://www.youtube.com/watch?v=QSZ-3wScePM


I wish we could embed video here.


I'm glad we can't embed video here. Embedded video is one of the most irritating inventions on the web.

 
markvent
646044.  Mon Dec 14, 2009 3:59 am Reply with quote

. .

 

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