K+ , Na+ , Ca+2

[Addallat]

TPR states Ca+2 is smaller than both K+ and Na+

can someone please explain the logic

Ty

pg 428. Hyperlearning workbook "Ca+2 ions are smaller than either Na+ or K+ ions"

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[Addallat]

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[loltopsy]

That is correct. Keep in mind that the radius of the nuclei is tiny compared to the radius of the actual atom. Most of the space is consumed by electrons.

The more electrons that are liberated from the electron shell, the stronger the positive charge of the overall atom. That charge comes from the nucleus. What is surrounded the nucleus? A negative cloud of electrons. So, they get sucked in closer to the nucleus creating a small overall radius for that ion. Calcium as a cation has the most charge and therefore can pull in electrons more stronger than sodium or potassium cations.

 

[Addallat]

That is correct. Keep in mind that the radius of the nuclei is tiny compared to the radius of the actual atom. Most of the space is consumed by electrons.

The more electrons that are liberated from the electron shell, the stronger the positive charge of the overall atom. That charge comes from the nucleus. What is surrounded the nucleus? A negative cloud of electrons. So, they get sucked in closer to the nucleus creating a small overall radius for that ion. Calcium as a cation has the most charge and therefore can pull in electrons more stronger than sodium or potassium cations.

Thank you for taking the time to reply!

ahhhhhhh so the bigger the atomic radius the smaller the resultant cations are??? because the bigger atomic radius + the greater number of protons since will have more of a drawing in effect resulting in a smaller size atom, right?

 

[deh2ase]

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[Addallat]

Na+ is isoelectronic with Ne while ca2+ and K+ are isoelectronic with Ar. Moving down a group you have increasing radius. Also Ca2+ has more protons in the nucleus so it can attract in the electrons to decrease radius size.

Na+<Ca2+<K+

ahhh had my atomic radius trend backwards


so one last question


so going down a group is more of an increase in atomic radius than going to the left? thus calcium has a bigger atomic radius than sodium?

 

[deh2ase]

ahhh had my atomic radius trend backwards


so one last question


so going down a group is more of an increase in atomic radius than going to the left? thus calcium has a bigger atomic radius than sodium?

Sorry thought I had the theory on it down but wiki proved me wrong.

http://en.m.wikipedia.org/wiki/Ionic_radius

 

[HesitantManatee]

so going down a group is more of an increase in atomic radius than going to the left? thus calcium has a bigger atomic radius than sodium?

All periodic trends are based on effective nuclear charge and size of the valence electron shell .You will never be asked to do a comparison like that unless they actually give you data. You can not compare atoms in a group with atoms in a row using more than one periodic trends, because their are more than one variable. You can predict the relative size of Ca+ and Na because they have the same valence electron shell but different effective nuclear charge.