[Stephen]

Questions:D
1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)
3.Why is configuration 1s²2p¹ excited state?
4.Why is Sb>Sn but Bi>Pb altrough same situation (p-electrons), I talk about atomic radius here!
5.Why is Ga smaller then Al?  I know that there are some irregulars in PSE but how am I suppose to recognize them?I know to that I have to watch electronic configuration to see is someone bigger or smaller but I couldn't find out the answers of those questions altrough I saw configuration.
6.How to see which ion is bigger when they're not from same group/period etc.
Na⁺<Ca²⁺ Mg²⁺>Ga³⁺, how to know those things?
7.Why is Ga³⁺ bigger than In³⁺?!
I don't get those sizes, pls *delete me*

[calciumoxide]

1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)

d orbitals are present starting from the element Sc to the last element and f orbitals start from La to the last element. I suggest you to read about quantum mechanics.

3.Why is configuration 1s22p1 excited state?

Ask yourself what the definition of excited state is.

[Phlogiston]

Questions:D
1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)

What is PSE? 

For both of these, do you know how to use the periodic table to write an electron configuration?  Or, where the d-block and f-blocks are?

3.Why is configuration 1s²2p¹ excited state?

Well, do you expect that to be the normal electron configuration for 3 electrons?

4.Why is Sb>Sn but Bi>Pb altrough same situation (p-electrons), I talk about atomic radius here!
5.Why is Ga smaller then Al?  I know that there are some irregulars in PSE but how am I suppose to recognize them?I know to that I have to watch electronic configuration to see is someone bigger or smaller but I couldn't find out the answers of those questions altrough I saw configuration.
6.How to see which ion is bigger when they're not from same group/period etc.
Na⁺<Ca²⁺ Mg²⁺>Ga³⁺, how to know those things?
7.Why is Ga³⁺ bigger than In³⁺?!
I don't get those sizes, pls *delete me*

Remember that there are two trends on the periodic table for atomic radius- one for groups and one for periods.  You can also use these trends together by thinking of them as a diagonal, or by thinking of an element that you can compare both a group and a period to.  As in, for example, comparing Mg and K, using Na as an intermediate.

[Stephen]

1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)

d orbitals are present starting from the element Sc to the last element and f orbitals start from La to the last element. I suggest you to read about quantum mechanics.

3.Why is configuration 1s22p1 excited state?

Ask yourself what the definition of excited state is.

Well when I write configuration of Lu I see that it's d element but when we look in periodic system of elements we can see that it is f element is it my mistake?


I know what is excited state but why this can't be a normal configuration ?
Why is this excited state?

[Stephen]

Questions:D
1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)

What is PSE? 

For both of these, do you know how to use the periodic table to write an electron configuration?  Or, where the d-block and f-blocks are?

3.Why is configuration 1s²2p¹ excited state?

Well, do you expect that to be the normal electron configuration for 3 electrons?

4.Why is Sb>Sn but Bi>Pb altrough same situation (p-electrons), I talk about atomic radius here!
5.Why is Ga smaller then Al?  I know that there are some irregulars in PSE but how am I suppose to recognize them?I know to that I have to watch electronic configuration to see is someone bigger or smaller but I couldn't find out the answers of those questions altrough I saw configuration.
6.How to see which ion is bigger when they're not from same group/period etc.
Na⁺<Ca²⁺ Mg²⁺>Ga³⁺, how to know those things?
7.Why is Ga³⁺ bigger than In³⁺?!
I don't get those sizes, pls *delete me*

Remember that there are two trends on the periodic table for atomic radius- one for groups and one for periods.  You can also use these trends together by thinking of them as a diagonal, or by thinking of an element that you can compare both a group and a period to.  As in, for example, comparing Mg and K, using Na as an intermediate.

PSE is periodic system of elements
I know writing an electronic configuration but when I need to see in what group element is I don't know when I have d and f elements!?But I do know to write them very well no problem with that....
Oooh my god?!I have just seen that this is 2p¹ not 2s¹ sorry Oh good...
For atomic and ionic radius:
I understand what do you want to tell me but this is situation when there are some irregulars....
I think you haven't paid an attention but just write configuration of all these expels and you'll See what I wanted to ask you!

[calciumoxide]

1.Well I am not sure  how to see in which group is element when I write  an electronic configuration...I know for s,p elements but I'm not sure when I see d and f elements...Can someone explain to me?
2.Why is Lu f-element?(PSE)

d orbitals are present starting from the element Sc to the last element and f orbitals start from La to the last element. I suggest you to read about quantum mechanics.

3.Why is configuration 1s22p1 excited state?

Ask yourself what the definition of excited state is.

Well when I write configuration of Lu I see that it's d element but when we look in periodic system of elements we can see that it is f element is it my mistake?


I know what is excited state but why this can't be a normal configuration ?
Why is this excited state?

Lu has 14 electrons in the 4f orbitals. I think you are confused about its valence electrons which, as you said, are in the d orbital. When you say it's f element do you mean it has electrons in the f orbital?

You asked why 1s²2p¹ is an excited state. If you know the definition of excited state, then you would know it is the state where an electron is located at a level higher than its normal energy state. In this case, for the normal state, it should be 1s²2s¹. But for the fact that you said it was 1s²2p¹, it is an excited state.

[Phlogiston]

For atomic and ionic radius:
I understand what do you want to tell me but this is situation when there are some irregulars....
I think you haven't paid an attention but just write configuration of all these expels and you'll See what I wanted to ask you!

What do you mean by "expels"?

Let me ask you this: what are the justifications for the atomic / ionic radius size trends?

[Stephen]

Examples, my keypad doesn't work fine:D
Well I know that there are rules such as that atomic radius along group raises and along period falls and for ionic radius I know that it raises along group and falls along period too....But When I see exact radius of some of the elements I see that there are some irregulars in those rules I said!So I asked how to know about those exceptions!?
For example:
Li>Be, Si>P but, He>H, Ne>F How to know that He is bigger then H or Ne is bigger then F?!There are more examples such as: Ga=Ge, Sb>Sn, Pb>Tl Po>Bi (these are along period) and Ga>Al (along group)
So what!?

[Stephen]

And just one more thing, How to observe the size of ions when they aren't from same group or period!?
Example:
Li⁺ and Mg²⁺
Na⁺ and Ca²⁺
Li⁺ and Ga³⁺
How am I suppose to know this?!
Do protons have something to do with this?Do I have to watch them to?

[Phlogiston]

Examples, my keypad doesn't work fine:D
Well I know that there are rules such as that atomic radius along group raises and along period falls and for ionic radius I know that it raises along group and falls along period too....But When I see exact radius of some of the elements I see that there are some irregulars in those rules I said!So I asked how to know about those exceptions!?
For example:
Li>Be, Si>P but, He>H, Ne>F How to know that He is bigger then H or Ne is bigger then F?!There are more examples such as: Ga=Ge, Sb>Sn, Pb>Tl Po>Bi (these are along period) and Ga>Al (along group)
So what!?

Ok, and what are the reasons for those rules? 

Also, how are you defining the size of He or Ne?  Because even though we imagine atoms to be tiny spheres, that's not actually true. 

[Stephen]

First question:
Well atomic radius raises along a group because each next has one level more and that's why he is bigger(radius is distance between center and last level)
And along period, well, each nest element has an electron more so that level become much more let's say more charged and forces between a nucleus and electrons become more attractive so whole that level is becoming to move up to nucleus!And how there are more and more electrons so that moving up is bigger and bigger so radius is getting smaller!

I don't know have I explained this well but I tried!:D

I don't answer on second question or I haven't understood it well:D

[Astrokel]

Hmm..you should understand periodic table is not perfect but it has provide chemists and us with convenient for many many years since the creation of it. So for now just accept the way it is and understand there will only be general rule in trends and not hard rules. I believe there are many people out there are trying to create a new periodic system..but we will see.

http://en.wikipedia.org/wiki/Van_der_Waals_radius (For comparison of size with noble gases)
http://en.wikipedia.org/wiki/D-block_contraction
http://en.wikipedia.org/wiki/Lanthanide_contraction

Check them out

[Stephen]

understand...but my explanations are based on the things that our chemistry teacher told us, so I learned it as I wrote up there!And I know also that those aren't rules which are always correct and that's why I asked you to explain it to me....How to know how to recognize those irregularities!?

[Astrokel]

Usually data will be provided and you will have to explain based on your knowledge on their electronic configuration and orbitals structure. There are many exceptions to the general trends but if you were to notice it, they are more or less the same, not exactly the same but i think you get what i meant. Just remember the basic rules and the links i have posted. Try to figure out the reasons behind those doubts you have posted and it will come it easy as you go along.

Let's start with Ga>Al

Why is it an exception? How do you explain this exception?

[Stephen]

I found out answer for this...because there is whole row of d-elements behind Ga and he has much more + charge so attractive forces are bigger then the ones in Al so he is smaller than Al!