Core charge confusion

[horizon]

I'm really confused about what core charge is.
I've understand that core charge remains constant down a group (because number of valence electrons are the same),however when you move down a group doesn't the force of attraction between the electrons and protons decrease because of increasing atomic radius?
Doesn't that then translate to a decreasing core charge as well?
What exactly is core charge? :buck2:

Thanks for those who answer my noob question.

[Water]

I kinda forgot my Unit 1/2 Chemistry, but hopefully, my chemistry is not too off the whack



Core Charge is basically used to explain the trend within the periodic table. For instance, it is the force in which it attracts the shells towards the nucleus. Hence, through the previous sentence, we can deride that, if it has a constant force of say +7, then as you have more shells,  the force of the core charge will have a lesser extent on the outside shells.

For example: You Have Fluorine with electronic configuration of 2,7. We know that it is a very small atom, the force between the 1st shell and the nucleus is very strong. This is explained by its Core Charge by being +7 (very stupid, I know)

A Contrasting Example to Fluoride is Francium, where it has 6 shells. The Core Charge, is still +7, however Francium is a much bigger atom than that of Fluorine. Core Charge explains this is the case, because the nucleus has a lesser pulling effect on the outside shells to the center.



Hopefully, my explanation is correct.





In Real Life Example




There's a very hot girl in the middle of the road. She will attract the closer guys, because they can see her very clearly and they want to go on a date with her and do all kinds of naughty stuff.

But as you move away from the girl, in a further distance, you see her as less attractive, but still attractive, so you will go nearer to see if she is hot or not.

Then say, you are  300m away from her, you don't know if she is beautiful or not, but you can see her just "hintly", so you won't be so inclined to go near her.



Therefore, we can say, that her attraction force is lesser, as the distance moves away from her. Similarly to Core Charge.

[pi]

Had to add that last part...

[iNerd]

Very impressive analogy - I will remember it now.

[horizon]

I kinda forgot my Unit 1/2 Chemistry, but hopefully, my chemistry is not too off the whack



Core Charge is basically used to explain the trend within the periodic table. For instance, it is the force in which it attracts the shells towards the nucleus. Hence, through the previous sentence, we can deride that, if it has a constant force of say +7, then as you have more shells,  the force of the core charge will have a lesser extent on the outside shells.

For example: You Have Fluorine with electronic configuration of 2,7. We know that it is a very small atom, the force between the 1st shell and the nucleus is very strong. This is explained by its Core Charge by being +7 (very stupid, I know)

A Contrasting Example to Fluoride is Francium, where it has 6 shells. The Core Charge, is still +7, however Francium is a much bigger atom than that of Fluorine. Core Charge explains this is the case, because the nucleus has a lesser pulling effect on the outside shells to the center.



Hopefully, my explanation is correct.





In Real Life Example




There's a very hot girl in the middle of the road. She will attract the closer guys, because they can see her very clearly and they want to go on a date with her and do all kinds of naughty stuff.

But as you move away from the girl, in a further distance, you see her as less attractive, but still attractive, so you will go nearer to see if she is hot or not.

Then say, you are  300m away from her, you don't know if she is beautiful or not, but you can see her just "hintly", so you won't be so inclined to go near her.



Therefore, we can say, that her attraction force is lesser, as the distance moves away from her. Similarly to Core Charge.

Thanks a lot! I GET IT NOW! Love the analogy btw.

[Martoman]

I kinda forgot my Unit 1/2 Chemistry, but hopefully, my chemistry is not too off the whack



Core Charge is basically used to explain the trend within the periodic table. For instance, it is the force in which it attracts the shells towards the nucleus. Hence, through the previous sentence, we can deride that, if it has a constant force of say +7, then as you have more shells,  the force of the core charge will have a lesser extent on the outside shells.

For example: You Have Fluorine with electronic configuration of 2,7. We know that it is a very small atom, the force between the 1st shell and the nucleus is very strong. This is explained by its Core Charge by being +7 (very stupid, I know)

A Contrasting Example to Fluoride is Francium, where it has 6 shells. The Core Charge, is still +7, however Francium is a much bigger atom than that of Fluorine. Core Charge explains this is the case, because the nucleus has a lesser pulling effect on the outside shells to the center.



Hopefully, my explanation is correct.





In Real Life Example




There's a very hot girl in the middle of the road. She will attract the closer guys, because they can see her very clearly and they want to go on a date with her and do all kinds of naughty stuff.

But as you move away from the girl, in a further distance, you see her as less attractive, but still attractive, so you will go nearer to see if she is hot or not.

Then say, you are  300m away from her, you don't know if she is beautiful or not, but you can see her just "hintly", so you won't be so inclined to go near her.



Therefore, we can say, that her attraction force is lesser, as the distance moves away from her. Similarly to Core Charge.

 :smitten:

[Mao]

I agree with the explanations given (nice analogy btw).

Just want to add that 'core charge' should be thought of as the 'effective charge' experienced by outer-shell electrons. The reason this charge is not the total charge of the nucleus is because inner shell electrons 'shield' the charge of the nucleus, effectively cancelling each other out. What remains is the 'core charge'.

Whilst this is a useful tool to use to predict trends and understand the periodic table, real physicists (read: not chemists) will frown upon this. This is not good solid science, but very useful nevertheless.