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Trends in atomic radius

Trends in atomic radius:

''As you move across a period, the nuclear charge increases. This means the electrostatic force of attraction between the positive nucleus and the negative outer electrons is stronger and therefore atomic radius decreases across a period.''


The electrostatic force of attraction refers to the force of attraction between the outer electrons and the nucleus right? Is this determined by the nuclear charge of the nucleus only, or are there other factors?
Reply 1
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clownfish
10
Original post by sabre2th1
Trends in atomic radius:

''As you move across a period, the nuclear charge increases. This means the electrostatic force of attraction between the positive nucleus and the negative outer electrons is stronger and therefore atomic radius decreases across a period.''


The electrostatic force of attraction refers to the force of attraction between the outer electrons and the nucleus right? Is this determined by the nuclear charge of the nucleus only, or are there other factors?


It's a balance between the nuclear charge and the shielding. There could be more protons in the nucleus, but if there's more shells between the nucleus and the outer electrons then the shielding will be higher and will outweigh the increase in nuclear charge, hence the nuclear attraction will be lower and the atomic radius will be higher.

ETA: This explains why the atomic radius increases down a group.
Reply 2
Avatar for sabre2th1
sabre2th1
OP
12
Original post by clownfish
It's a balance between the nuclear charge and the shielding. There could be more protons in the nucleus, but if there's more shells between the nucleus and the outer electrons then the shielding will be higher and will outweigh the increase in nuclear charge, hence the nuclear attraction will be lower and the atomic radius will be higher.

ETA: This explains why the atomic radius increases down a group.


So as the number of protons increases, the electrostatic forces of attraction between the nucleus and outer electron increases (as long as the shielding remains the same)? Thanks.
Reply 3
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clownfish
10
Original post by sabre2th1
So as the number of protons increases, the electrostatic forces of attraction between the nucleus and outer electron increases (as long as the shielding remains the same)? Thanks.


Exactly. :smile:

This is the case as you go across a period.
Reply 4
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sabre2th1
OP
12
Original post by clownfish
Exactly. :smile:

This is the case as you go across a period.


Thank you :smile:

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