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### Topic: Chemistry energy help ?  (Read 7066 times)

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#### Shahab Mirza

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##### Re: Chemistry energy help ?
« Reply #15 on: October 06, 2014, 08:30:49 AM »
The quantum number n denotes the successive electron shells, so n=1 is K, n=2 is L, n=3 is M, n=4 is N and so on.
Corribus has already given the best answer to this question, I don't see what else I can say.
The question is probably alluding to the fact that e.g. for potassium the electron configuration is 1s22s22p63s23p64s1, i.e. the outermost electron goes in 4s (answer B) rather than 3d (answer A) as might be expected. In this case then, A is the higher energy. But the relative energy of these orbitals varies with atomic number.

sir listen, corribis said this
"For a multi-electronic atom, this changes because the l quantum number impacts energy (due to penetration and shielding effects). Here we're basically being asked what fills first: the 3d or 4s orbital when putting multiple electrons into hydrogenic orbitals. The 3d is usually filled first"
now i just want to know that what is relations betwwen 3d orbital and l quantum number how we know?

#### Shahab Mirza

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##### Re: Chemistry energy help ?
« Reply #16 on: October 06, 2014, 08:32:14 AM »
The quantum number n denotes the successive electron shells, so n=1 is K, n=2 is L, n=3 is M, n=4 is N and so on.
Corribus has already given the best answer to this question, I don't see what else I can say.
The question is probably alluding to the fact that e.g. for potassium the electron configuration is 1s22s22p63s23p64s1, i.e. the outermost electron goes in 4s (answer B) rather than 3d (answer A) as might be expected. In this case then, A is the higher energy. But the relative energy of these orbitals varies with atomic number.
sir listen the corribis said that
"For a multi-electronic atom, this changes because the l quantum number impacts energy (due to penetration and shielding effects). Here we're basically being asked what fills first: the 3d or 4s orbital when putting multiple electrons into hydrogenic orbitals. The 3d is usually filled first"

i want to know that what is relation between 3d and l quantum number?

#### Shahab Mirza

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##### Re: Chemistry energy help ?
« Reply #17 on: October 06, 2014, 08:37:17 AM »
The quantum number n denotes the successive electron shells, so n=1 is K, n=2 is L, n=3 is M, n=4 is N and so on.
Corribus has already given the best answer to this question, I don't see what else I can say.
The question is probably alluding to the fact that e.g. for potassium the electron configuration is 1s22s22p63s23p64s1, i.e. the outermost electron goes in 4s (answer B) rather than 3d (answer A) as might be expected. In this case then, A is the higher energy. But the relative energy of these orbitals varies with atomic number.

Thank you all , Sir its good for me that I reviewed corribis's answer and came to knew that he was right as he said that the in case of multielectrons l matters because of high penetrating power it affects energy thats why in the answer l=2 means more enrgy and hence is answer , right? was this the thing in which i was confusing.?

#### mjc123

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##### Re: Chemistry energy help ?
« Reply #18 on: October 06, 2014, 11:43:45 AM »
Yes. For electrons in the same shell, the s orbital (l=0) is more penetrating than the p orbital (l=1), so feels more of the nuclear charge, and has lower energy. Similarly p is lower energy than d (l=2), and so on. For the higher shells, these ranges of orbital energies overlap, so e.g. 4s is lower than 3d.

#### Corribus

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##### Re: Chemistry energy help ?
« Reply #19 on: October 06, 2014, 11:50:41 AM »
@Shahab Mirza

Maybe this Chemguide page will help.

http://www.chemguide.co.uk/atoms/properties/3d4sproblem.html
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

#### Shahab Mirza

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##### Re: Chemistry energy help ?
« Reply #20 on: October 06, 2014, 12:51:46 PM »
Thanks all of you , you are doing a good thing Sir helping students in education and all that is amazing , hats off , and thanks alot once again , Sir MJC123 and Sir Corrobis . I understood this concept , it will also help me to solve other related such problems =D

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##### Re: Chemistry energy help ?
« Reply #21 on: October 07, 2014, 12:25:15 AM »
In short you Can do these kind of question by Aufbau Principle ,

which electron have greater value of n+l , its energy will be higher.
1. n = 3 , l = 2 , then n+l = 5
2. n=4. , l= 0. , then n+l = 4

BTW Bro , dont call me sir , i am in High school , i think i'm your junior as you said that you have passed high school.
« Last Edit: October 07, 2014, 12:45:46 AM by adidx »