1.5 Atomic structure and the periodic table
Posted by: intechemistry on: September 23, 2010
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8 Responses to "1.5 Atomic structure and the periodic table"
December 27, 2010 at 6:04 pm
Salam.
Because a subshell is part of a shell, then any subshell contribution to shielding effects is automatically a property of the parent shell. and as new shells cause the greatest change in shielding then shells deserve our attention more rather then the subshells.
May 5, 2011 at 7:33 am
salam
sir, if we have to draw ionic dot and cross diagram for ionic compound and only outer electrons are shown, let’s say NaCl.do we have to draw the 8 electrons around Na+ ion, since it has donated the only outer electron to Cl?
all this while i’ve been drawing the 8 electrons and i thought it’s correct, but in revision guide, they dont draw the 8 electrons
May 5, 2011 at 11:21 am
Salam.
I think both are accepted should the question say something like ‘showing the outer electrons’. Personally, in such an instance, I would say (for the cation), that once the outer shell electrons are lost the previously inner shell now becomes the new outer shell so the electrons in that shell become the outer electrons and should be shown – as you have done.
Its possible a question may ask something like: “showing the valence shell” in which case you can only draw one thing… an empty shell, i.e. a circle with no ‘electrons’ on it as the inner shell – now exposed of course – wasn’t the valence shell and still isn’t the valence shell after the old outer shell was lost.
So look for specific wording in the Q, but the case in the first paragraph is usually what they ask for.
July 20, 2011 at 9:53 pm
why do the hydrated nickel sulfate incorporate with 7 molecules of water and copper (II) sulphate incorporate with 5 molecules of water? Is it the exact and constant value or we need to do some calculations to find the number of molecules of water?
July 24, 2011 at 2:46 am
My guess is because of the differences in size of the metal ions Cu2+ and Ni2+ as well as the different different bond strengths between the water, metal ion and anion. You will discuss this kind of bonding in Unit 5, Topic 5.3.
For now it may be useful to think about 50 cen coins. Lying flat on a table, you can get something like 5 or 4 coins around one single coin. But if you have a saucer or small plate you can get more coins around the circumference. Also their crystal structures may (I don’t actually know their structures) be different hence, one structure may be need more water to accommodate the crystal shape.
If you want a method to tell you how many waters a particular compound has, then I’m afraid I’ll disappoint you as I don’t know any sure fire ways to derive the correct numbers :s
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December 26, 2010 at 6:14 pm
Salam sir..
Can i say that the subshells is the one that cause the shielding effect of an atom of an element?