Shielding and Effective Nuclear Charge

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104785906
Posts: 11
Joined: Wed Nov 16, 2016 3:04 am

Shielding and Effective Nuclear Charge

Postby 104785906 » Mon Jul 10, 2017 8:47 pm

Hi there,

Can someone better explain the relationship between shielding and effective nuclear charge? To my understanding, shielding reduces this charge, but physically, what is happening to the electrons inside the nucleus. Is the charge reduced because there is no need to have so much power to pull electrons away from the nucleus' attracting force since these are shielded? As so, is an s orbital more effective at shielding than a p orbital ?

Sarah_Wilen
Posts: 62
Joined: Fri Jun 23, 2017 11:39 am
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Re: Shielding and Effective Nuclear Charge

Postby Sarah_Wilen » Tue Jul 11, 2017 12:29 am

I liked the example Dr. Lavelle used in class for shielding, so I will retell it in my own jumbled up way. He explained, imagine you are at a campfire. There is a fire pit in front of you and you are feeling this nice heat radiating from it. You like the heat and feel an inclination towards it like it is pulling you into its warmth. Then, 2 of your annoying friends decide to stand in front of you, but that's fine, you let them stand there because you are nice. The heat is now radiating to your 2 friends, and the net warmth you feel is much less now :(

Now, into chemistry words. Let's say you are an electron in energy level 3. In this model, you are the valence electrons. You have 2 friend electrons standing in front of you, they are in energy levels 1 and 2. Your friends are the core electrons The fire pit is the nucleus of the atom and has a positive pull on you and your 2 friends as electrons. When your friends are in front of you messing up your vibe, they are "shielding" you from the heat. In Chem words, the core electrons are shielding the valence electrons from the nucleus pull of attraction, so the net pull from the nucleus is felt less by the valence electrons. This is the Zeff or net effective nuclear charge.

Hope this somewhat helps!

104785906
Posts: 11
Joined: Wed Nov 16, 2016 3:04 am

Re: Shielding and Effective Nuclear Charge

Postby 104785906 » Tue Jul 11, 2017 3:26 pm

sure does, thanks!


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