Ionic Radius Trends and Multiple Ionization Energies

negatively charged ions

form when atoms GAIN electrons

​Anions

positively charged ions​

form when atoms LOSE electrons

​Cations

Some text here about the topic of discussion

negatively charged ions

form when atoms GAIN electrons

​Anions

positively charged ions​

form when atoms LOSE electrons

​Cations

Some text here about the topic of discussion

​Ionic radius trends

Cations typically have a SMALLER radius than the parent atom

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​Cations vs parent ion

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Cations typically have a SMALLER radius than the parent atom

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• Fewer electrons

• Fewer electron:electron repulsions

• Fewer occupied energy levels

Anions typically have a larger radius than the parent ion​

​Anions vs parent ion

​r

​Some text here about the topic of discussion.

More electron-electron repulsions​

​Anions typically have a larger radius than the parent atom

​r

What is the trend down a group?

What is the trend across a period?​

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​Ionic radius trends

Ionic radius increases down a group​

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​Ionic radius trends

Ionic radius decreases from L --> R for cations

Jumps up for anions, then decreases​

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​Ionic radius trends

• The energy required to remove the outermost electron from an isolated gas phase atom

• The energy required to remove a second electron

• You can have as many ionization energies as there are electrons in the neutral atom

• This graph shows the first 7 ionization energies for sodium

• As you remove more and more electrons, it takes more and more ionization energy

• Consider the values for the first and second ionization energies of sodium

• Removing the first electron from Na is relatively easy

• To remove a second electron from Na, we have to remove an electron from a noble gas-like electron configuration

• We see a BIG jump in IE values once all the valence electrons have been removed

• IE₂ > IE₁, as expected

• We see a big jump between IE₂ and IE₃

• Removing both electrons from the 3s sublevel is relatively easy

• Once we try to remove an electron from a fully filled energy level, it takes a LOT more energy!

• This confirms 2 valence electrons for Mg