Shielding effect

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Deepika Pugalenthi 1A
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Joined: Fri Sep 28, 2018 12:24 am

Shielding effect

Postby Deepika Pugalenthi 1A » Wed Oct 24, 2018 10:18 am

How does shielding work and how does that affect electrostatic attraction of the electrons to the nucleus? Thank you!

Saman Andalib 1H
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Joined: Fri Sep 28, 2018 12:16 am

Re: Shielding effect

Postby Saman Andalib 1H » Wed Oct 24, 2018 11:05 am

The shielding effect basically describes the reduced attraction of a nucleus to its electrons the more filled energy levels there are. For example, in terms of electron ionization energy, it would be much easier to remove an electron from Potassium (4s1) rather than Lithium (2s1) because of the greater shielding the Potassium atom has from the attraction of the nucleus.

Olivia Young 1A
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Re: Shielding effect

Postby Olivia Young 1A » Wed Oct 24, 2018 11:16 am

The shielding effect is how the inner electrons (in the lower energy levels) decrease the attractive pull of the nucleus on the outer electrons (in the highest energy levels). Therefore, the electron-electron repulsion between electrons on different energy levels reduces the electrostatic attraction between the nucleus and the valence electrons, resulting in the effective nuclear charge. In atoms with many electrons, the shielding effect is more prominent because there is a greater number of electrons to experience the electron-electron repulsion, which results in a lower attractive force with the positively-charged nucleus. This shielding effect explains why its easier to remove electrons from the valence shell.

MaanasO 1A
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Re: Shielding effect

Postby MaanasO 1A » Wed Oct 24, 2018 1:43 pm

Hi Deepika!

Shielding refers to the electron-electron repulsion forces that counter the attractive forces between the nucleus and the individual electrons. When you have electrons that are closer to the nucleus on average, they provide repulsion forces that greatly reduce the effective nuclear charge (there's a bunch of physics involved; Coulomb's Law is probably the best way to mathematically explain how the electrons reduce the nuclear charge). The closer electrons provide repulsion forces away from the nucleus, meaning the further away

If you have an electron in the 2p state, there are 4 e- closer to the nucleus (2 in the 1s state and 2 in the 2s state). These electrons shield the 2p electron from the nuclear charges by providing electron-electron repulsion forces. Similarly, the 1s electrons also shield the 2s electrons because the 1s electrons are closer and provide a repulsion force against the attractive force between the 2s electrons and the protons of the nucleus.

Hope that helps!

George Ghaly 2L
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Re: Shielding effect

Postby George Ghaly 2L » Fri Oct 26, 2018 12:26 am

Shielding protects the outer electrons from the pull of the nucleus through the inner electrons absorbing the pull.

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Re: Shielding effect

Postby lindsey_ammann_4E » Sat Oct 27, 2018 11:01 pm

For me, it helps to use the bonfire metaphor that Dr. Lavelle mentioned in lecture. Let's say you're an electron sitting close to the fire. If another person (another electron) sits or stands in between you and the fire, then you will feel less heat (or attraction) to the fire (nucleus). In a sense, the person shields you from the fire as an electron can shield another electron from the pull of the nucleus.

Riya Shah 4H
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Re: Shielding effect

Postby Riya Shah 4H » Sat Nov 17, 2018 9:30 pm

Shielding effect is when electrons in the shells closer to the nucleus block the effect of the protons in the nucleus on other electrons in the outer shells.

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