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ionic radii

Posted: Tue Nov 05, 2019 10:57 pm
by Jared_Yuge
why is it that an anion has a larger radius than its parent atom, I thought that when we add electrons the attraction gets stronger with the nucleus and it gets pulled in making it smaller.

Re: ionic radii

Posted: Tue Nov 05, 2019 11:16 pm
by Justin Vayakone 1C
Actually, when we add electrons, the attractive pull between the nucleus and electrons are weaker. With more electrons to pull in, the force is weaker. There is also added repulsion between the electrons that cause them to be further apart, creating a larger radius.

Re: ionic radii

Posted: Thu Nov 07, 2019 11:44 am
by Charysa Santos 4G
An anion has a larger radius than its neutral atom because when you add an electron, the repulsive forces between the electrons is relatively greater than the pull of the positively-charged nucleus, thus causing the electrons to further apart, making the anion's radius larger.

Re: ionic radii

Posted: Thu Nov 07, 2019 11:52 am
by Jasmine Fendi 1D
In addition to the comments above, the atomic radii decreases as you move towards the right of a period. This is because as you move right, the added electrons are added to the same n level but the number of protons in the nucleus increases. The protons have a much greater effect than the added electrons, so the protons actually have more pull on the electrons towards the nucleus.

Re: ionic radii

Posted: Thu Nov 07, 2019 12:40 pm
by Claire Grover 3G
As the people above said, cations are larger than the neutral atoms because there are more electrons that are pushing against each other and expanding the radios. The atomic radius of neutral elements decreases across a period because there are also increasing amounts of protons pulling in the electrons more and more. With a cation, an electron is added but no proton, so it doesn't become smaller.