Ionic radius trends
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Ionic radius trends
Does ionic radius increase or decrease as the charge gets more positive? How can this be explained in terms of nuclear attraction and shielding?
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Re: Ionic radius trends
The ionic radius is the distance between the nucleus and the electron in the outermost shell. When a cation is formed, this loss of an electron decreases shielding because that electron can no longer shield the other electrons from the nuclear pull. The stronger nuclear pull causes a decreased ionic radius. When an anion is formed, the gain of an electron increases shielding because the added electron repels other electrons, resulting in an increased ionic radius.
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Re: Ionic radius trends
Hi! As the charge become more positive, the ionic radius usually decreases. This is because there are fewer electrons in the atom. As there are fewer electrons, the electrons are pulled closer to the nucleus of the atom. When an ion is more negative, the ionic radius increases because the electrons repel eachohter (similar to magnets repelling each other.
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Re: Ionic radius trends
Another way of thinking about the relationship between radius and charge is to remember that electrons are what make up the majority of the size of an atom, so when an ion loses electrons and becomes more positively charged, the overall size of the atom decreases as a result.
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Re: Ionic radius trends
Heidi Buri 2I wrote:Hi! As the charge become more positive, the ionic radius usually decreases. This is because there are fewer electrons in the atom. As there are fewer electrons, the electrons are pulled closer to the nucleus of the atom. When an ion is more negative, the ionic radius increases because the electrons repel eachohter (similar to magnets repelling each other.
Thank you for your explanation! It made it easier to understand.
Re: Ionic radius trends
I agree with everyone else above. Increasing or decreasing the amount of electrons alters its ionic radius as electrons have a significant contribution to an atoms size.
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Re: Ionic radius trends
When there is a higher positive charge, that means that there is a higher number of protons than there are electrons. The electrons and protons attract each other, so if there are more protons, it will pull more of the electrons in. Also, with a lost electron, there would be less repulsion between the energy levels and result in a smaller radius.
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