[Krystie]

Ok, so this is something for high school - a mod can move it to high school if they want but i dont think i really want tat kinda help

i have to talk about why hydrogen is where it is on the P.T.

now, my research has pointed out that it can be placed with the halogens but is most commonly in Group 1, yet so far i am getting more reasons why it should be a halogen

so very urgently, can you just contribute some knowledge, opinion, commenting whatever, tat may help me to convince why its most commonly in group 1

thanks  

[gayathri1989]

HELLO
   IT IS GENUNE TO START A PERIODIC TABLE WITH LEAST  NUMBER  

[Borek]

now, my research has pointed out that it can be placed with the halogens but is most commonly in Group 1, yet so far i am getting more reasons why it should be a halogen

Could you write these reasons down here?

[Krystie]

Why Group 1
* most commonly REACTS with halogens
*one electron in outtermost (only) shell

Why Group 7
*Poor conductor of heat & electricity (group 1 are good conductors)
*Non-metal (group 1 is metals)
*CAN react with alkali metals
*Oxidation number -1.

gayathri1989 - thanks for your contribution but my understanding is, if it was at the top of group 7, it was still be the beginning of the periodic table as He is the second and its at the top of group 8??

Thank you

[Borek]

Why Group 1
*one electron in outtermost (only) shell

And that's enough, as PT is build around the electron configuration of elements.

Why Group 7
*Poor conductor of heat & electricity (group 1 are good conductors)
*Non-metal (group 1 is metals)

Metallic hydrogen has already been reported by physicists, so both arguments are no longer valid. Besides, metallicity gets stronger when you move down the PT and hydrogen - being at the very top - has all rights to be non-metallic.

*CAN react with alkali metals
*Oxidation number -1.

These are good ones. However, the problem with PT is that all light (not in terms of density, but on terms of nucleus mass and size) elements are different from their heavy cousins from the same PT groups - is B similar to Al? No. C to Pb? No - and so on.

[Mitch]

How about electronegativity?

[Donaldson Tan]

well.. hydrogen exhibit metallic behavior at extremely high pressure. the atomic orbitals overlap in a continuum fashion to product a conductance band at such condition. this is metallic behavior. however, at normal conditions, H spontaneously form H2 molecule, and this "inhibits" the metallic behavior.

actually, isnt the periodic table arranged by proton number? H contains 1 valence electron and therefore it's Group I.

[jdurg]

When you think about the stability of the hydrogen ions, however, what is more stable in aqueous solution; the H+ ion or the H- ion?  The H+ ion is by a long margin.  Most hydrides that I know of are not very stable and will quickly react with other things.  Most compounds that I know of which have hydrogen in a positive oxidation state are quite stable.  (NaOH, H2O, CH3CH2OH, etc. etc).  Another thing to consider is that hydrogen actually is a metal but with an INCREDIBLY low melting point.  If you solidify fluorine, chlorine, bromine, and iodine you still have non-metal elements.  If you solidify hydrogen, however, it actually is a metal.  So I think that hydrogen is placed where it is not only for aesthetic reasons, but for chemical reasons as well.

Why Group 7
*Poor conductor of heat & electricity (group 1 are good conductors)
All gaseous elements are pretty poor conductors of heat and electricity.

*Non-metal (group 1 is metals)
At room temperature, but if turned into a solid it basically is a metal.

*CAN react with alkali metals
MUCH more readily reacts with the halogens.  Put some chlorine and hydrogen together and just add some light and they'll react.  You have to coerce Hydrogen into reacting with the alkali metals.

*Oxidation number -1.
Not very stable with an oxidation number of -1.  Far more stable with an oxidation number of +1.  Also, the alkali metals can exist with an oxidation state of -1, but again, their stability is virtually non-existant.

[yipster]

hydrogen is the "lightest" element making it number one i think?

what i dont grasp is how hydrogen burned with oxygen forms a (heavy) liquid  while it needs to be cooled to be liquified as an element. what does that tell me?

does anybody know of a hydrogen info site explaning this in some detail?

[Borek]

what i dont grasp is how hydrogen burned with oxygen forms a (heavy) liquid  while it needs to be cooled to be liquified as an element. what does that tell me?

All chemistry is about that - new compounds are different from the compounds that reacted. You mix two white substances and you get something red, or yellow, or kaboom...

Hydrogen is no different.

[Mitch]

what i dont grasp is how hydrogen burned with oxygen forms a (heavy) liquid  while it needs to be cooled to be liquified as an element. what does that tell me?

Because H2O loves to form hydrogen bonds. Good question, keep learning, its good for you.