ALL CIE CHEMISTRY DOUBTS HERE !!

[Twinkle Charms]

hello all =]
just been two days i started chem A level (both AS & A2) and any doubts i find ill be postin here...


so my first doubt,
can someone please clearly explain me what orbitals are
accordin to the definition, it says tht they are space around the nucleus where there is max. probablity of findin the electron within its orbit.
for example when n=3; l=0,1,2
so by 0,1,2 does it mean 0 from the nucleus (like coverin all the orbits in between as well> n=1 and n=2)

[elemis]

I too have just started my AS Levels.

I wish Nid was here to explain this stuff. She's the Chem Masta. 

[Twinkle Charms]

I too have just started my AS Levels.

I wish Nid was here to explain this stuff. She's the Chem Masta. 

ohh sad =[
yeah i posted on her fb to get back soon, hope the lady checks it out =|

[Aadeez || Zafar]

ORbital:- u cn just make it clear that by understanding that they r the sub-shell of energy level.

for eg.

shell one contains oribtal - 1s(2e-) (grand Total 2e-)
shell two contains orbital - 2s (2e-), 2p(2*3 e-(px,py,pz) (grand total 8e=(2e-+6e-)
shell three contains ornital - 3s(2e-), 3p(2*3e-), 4s(2e-), 3d(2*5e-) (element in which electrons are filled in 3d would be transition metal) [grand total 20e-)

soory!
my explain skill is very poor

[nid404]

http://www.chemguide.co.uk/atoms/properties/atomorbs.html#top

And check www.knockhardy.co.uk for ppts.

If you still don't understand(rare case) then I shall do my bit 

[Twinkle Charms]

thanks nid, i got what i wanted to.

@Harsh
we havnt reached tht bit yet, we'll be doin it tom hopefully
buh im really thankful to you for atleast sparing a min here

[Aadeez || Zafar]

At which session did u gave ur IGCSE?

[Twinkle Charms]

At which session did u gave ur IGCSE?

june 2009

[Arthur Bon Zavi]

june 2009

Too Early and it's too late to start AS/A Levels, don't u think so?

[Twinkle Charms]

Too Early and it's too late to start AS/A Levels, don't u think so?

ohh yeaa too late  NOT actually
hahaa
i gave my physics & maths A level (AS & A2) in june 2010
n now in june 2011 ill be giving chem Alevel and ict AS 

[Arthur Bon Zavi]

ohh yeaa too late  NOT actually
hahaa
i gave my physics & maths A level (AS & A2) in june 2010
n now in june 2011 ill be giving chem Alevel and ict AS 

Ohh!! Best Of luck with your subjects and keep posting the doubts right here!! 

[Twinkle Charms]

Ohh!! Best Of luck with your subjects and keep posting the doubts right here!! 

thanks theonlyone =]


So can anyone suggest why the relative atomic mass of Martian oxygen is different from that of oxygen obtained from earth?

[Deadly_king]

thanks theonlyone =]


So can anyone suggest why the relative atomic mass of Martian oxygen is different from that of oxygen obtained from earth?

The analysis of a sample of Martian air collected by the Phoenix Lander shows that the ratio of oxygen and carbon dioxide isotopes present in the atmosphere of Mars is very similar to that of Earth. Due to Mars’ low gravity and lack of magnetic field, lighter isotopes are lost to space and so an older atmosphere will consist of mainly ^heavier isotopes.

In other words the oxygen on Mars would consist mainly of O¹⁸ while on Earth our oxygen consist mainly of O¹⁶.

Hope it helps clear your mind about that

[Twinkle Charms]

In other words the oxygen on Mars would consist mainly of O¹⁸ while on Earth our oxygen consist mainly of O¹⁶.

Hope it helps clear your mind about that

oohhh thanks


The first 4 ionisation energies of an element are 590, 1150, 4940 and 6480 KJ mol-1. Suggest the group in periodic table to which this element belongs.  [I have the answer from the back of the text, buh dont understand it =\ so i want explanation please =] )

[Deadly_king]

oohhh thanks


The first 4 ionisation energies of an element are 590, 1150, 4940 and 6480 KJ mol-1. Suggest the group in periodic table to which this element belongs.  [I have the answer from the back of the text, buh dont understand it =\ so i want explanation please =] )

From the given values, we can note a very significant rise (more than twice) from the second ionisation energies to the third ionisation energies. This suggest that there has been a change in orbitals(more precisely shell number) which proves that the element has two electrons in its outermost shell.

Therefore the element is in group 2.

Did you get me??
If not......let me know and i'll try to elaborate more