HW 1E.5

Norman Dis4C
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

HW 1E.5

Can someone explain this sentence to me: Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbital can penetrate to the nucleus of an atom.

What does it mean to penetrate to the nucleus of an atom?

Reina Robles 2B
Posts: 71
Joined: Fri Aug 09, 2019 12:16 am

Re: HW 1E.5

In chemistry, penetration means an electron's probability density near the atom's nucleus. In other words, how close an electron can get to the nucleus.

s-electrons of any shell can be close to the nucleus/have greater penetration, while the electrons of other subshells (p, d, etc.) have less penetration. I hope this helps!

JasonLiu_2J
Posts: 109
Joined: Sat Aug 24, 2019 12:17 am

Re: HW 1E.5

To add on to what was previously said, electrons in the s-orbital has a symmetrical electron density distribution in a spherical shape about the nucleus. That is, the s-orbital electrons have a greater ability to penetrate to the nucleus because they have a higher probability to be found at or near the nucleus of an atom. This then gives them a greater ability to repel outer electrons from the charge of the nucleus(greater shielding), because they are directly between the electrons in outer orbitals and the nucleus. In contrast, p-orbitals have a non-symmetric electron density distribution because they have two nodes on either side of the nucleus and a nodal plane at the nucleus. This nodal plane means that there is zero probability for electrons of the p-orbital to be found at the nucleus, and the nodes on either side indicate that electron density distribution/probability is highest when you are farther away from the nucleus before returning to zero when very far. This electron density distribution leads to lesser penetration and lesser shielding. Since the electrons are found farther away from the nucleus, they do not penetrate to the nucleus and have less ability to repel those in outer orbitals from the positive attraction of the nucleus. Hope this helps with your question!

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