Atomic radii

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Marni Kahn 1A
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Atomic radii

Postby Marni Kahn 1A » Wed Oct 16, 2019 4:20 pm

Why do atomic radii generally decrease from left to right across a period if the atomic number is increasing(# of electrons/protons)?

Kaitlyn Ang 1J
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Re: Atomic radii

Postby Kaitlyn Ang 1J » Wed Oct 16, 2019 4:22 pm

As there are more valence electrons (aka from left to right on the periodic table), the attraction between the valence electrons and the nucleus grows stronger, so the electrons gravitate closer, making the radius smaller

Michelle Chan 1J
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Re: Atomic radii

Postby Michelle Chan 1J » Wed Oct 16, 2019 4:23 pm

Since the number of protons is increasing as you go right on the periodic table, the the effective nuclear charge increases and the nuclear pull is greater, thus resulting in a smaller radii.

WesleyWu_1C
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Re: Atomic radii

Postby WesleyWu_1C » Wed Oct 16, 2019 4:26 pm

So even though when you move right to left the electrons are increasing, there will also be more protons which pulls in the electrons slightly more. This leads to a smaller radii.

Ruby Richter 2L
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Re: Atomic radii

Postby Ruby Richter 2L » Fri Oct 18, 2019 3:37 pm

As has been mentioned, since the number of protons increases, the nucleus gets bigger and attracts more electrons, so it's essentially pulling in the electrons that surround it which makes the atom as a whole smaller.

Eunice Nguyen 4I
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Re: Atomic radii

Postby Eunice Nguyen 4I » Fri Oct 18, 2019 4:21 pm

Within a period or family of elements, all electrons are added to the same shell. At the same time, protons are being added to the nucleus, making it more positively charged, which further indicates greater nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom's shell closer to the nucleus. The valence electrons are held closer towards the nucleus of the atom, which decreases the atomic radius.

kendal mccarthy
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Re: Atomic radii

Postby kendal mccarthy » Sun Oct 20, 2019 2:14 pm

This has to do with the number of valence electrons along with the increasing number of protons in the nucleus as you go from left to right across the periodic table. This trend causes the protons to have a greater pull over the electrons, thus leading to a smaller atomic radius.

Joelle 3L
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Re: Atomic radii

Postby Joelle 3L » Sun Oct 20, 2019 2:22 pm

Atomic radii is one of the periodic trends. Atomic radius decreases as you move to the right of the period table because electrons are being added to the same shell but also protons are added to the nucleus. This would mean it makes it more positively charged and therefore greater nuclear attraction. Thus, the atom's shell is pulled closer to the nucleus and making the radius smaller.

Tahlia Mullins
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Re: Atomic radii

Postby Tahlia Mullins » Sun Oct 20, 2019 8:28 pm

I think it is important to stress theft that the electrons are being added to the same shell when moving from left to right, therefore the atomic radius does not increase too drastically. At the same time, there are more protons in the nucleus, pulling the electrons in closer, decreasing the atomic radius.

Shail Avasthi 3C
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Re: Atomic radii

Postby Shail Avasthi 3C » Sun Oct 20, 2019 8:52 pm

As you move right across a row in the periodic table, the positive charge of the nucleus becomes greater due to the increasing number of protons. This causes the nucleus to have a greater pull on the electrons, thereby decreasing the atomic radius. This is the effect of effective nuclear charge.


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