Effective nuclear charge and periodic trends

[rottenapple]

Please help me!

According to Zeff- Fluorine should be 1. the most electronegative atom? 2. has the highest e- affinity? 3. release the most energy when form bond?

why is N not as small as F? I'm thinking that its outter most electrons are the same distance from its nucleus (comparing to F) but not enough nuclear charge to pull it in?

How does Zeff explains electronegativity?

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[rottenapple]

Thank you!

 

[fizzgig]

right on N vs F size --> when you add a whole new shell level (periodic table row) you're adding a proton but also an electron at a much higher energy level/farther distance, so size goes up. as you move across the periodic table, adding a new shell type (s to p, for example) bumps up size some but not as much as shell level. and moving from left to right within the P subshell you're adding an electron at about the same energy as the last one you added (adding pz to px and py...), so all of the P electrons can see more of this proton you added. Zeff goes up, radius goes down.

 

[ilovemcat]

Zeff = Nuclear Charge - Shielding Electrons

Fluorine is atomic element number 9, thus 9 protons make up the Nuclear Charge. There are 2 shielding electrons in the 1s² orbital.

Calculating the Zeff is simple. Zeff = 9 - 2 so Fluorine has an effective nuclear charge of +7.

As you go down a row on the periodic table, the number of shell electrons remains constant while the number of Protons increase, thus increasing Zeff. This is why the size of atoms decrease as you move down the each row of the periodic table but then rapidly increases as you drop to first column of the next row.

 

[rls303]

Zeff = Nuclear Charge - Shielding Electrons

Fluorine is atomic element number 9, thus 9 protons make up the Nuclear Charge. There are 2 shielding electrons in the 1s² orbital.

Calculating the Zeff is simple. Zeff = 9 - 2 so Fluorine has an effective nuclear charge of +7.

As you go down a row on the periodic table, the number of shell electrons remains constant while the number of Protons increase, thus increasing Zeff. This is why the size of atoms decrease as you move down the each row of the periodic table but then rapidly increases as you drop to first column of the next row.

So as we go to the right we add protons but no more shells, so more effective nuclear charge felt by those electrons that are successively to the right?