about the properties of ionic and metallic substances What can we learn about the properties of ionic and metallic substances by looking at their atomic structure?

etc etc The sodium chloride crystal stays together due to (+) and (-) electrostatic attractions.

Here is an example of a metallic crystal. Note its similarity to the organization of an ionic crystal. Here, however, all the ions are positive. HOW CAN THAT BE? How can (+) ions stick together?

As an example metal, Let’s take a look at aluminum’s subatomic structure ALUMINUM

The aluminum particles are arranged in an orderly repeating pattern.

However the valence electrons are not localized to any one particle. They are free to move and occupy the space between the (+) ions. ALUMINUM

The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. ALUMINUM

cations (+ ions) The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. cations (+ ions) ALUMINUM

cations (+ ions) The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. cations (+ ions) ALUMINUM

cations (+ ions) The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. cations (+ ions) ALUMINUM

freely moving valence electrons The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. freely moving valence electrons ALUMINUM

freely moving valence electrons The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. freely moving valence electrons ALUMINUM

freely moving valence electrons The large attraction of the (+) ions for the (-) delocalized valence electrons are what holds the crystal together. freely moving valence electrons ALUMINUM

ALUMINUM

ALUMINUM

3+ ALUMINUM

Our example of aluminum metal consists of Al3+ ions, with each Al atom giving up 3 electrons to the delocalized ‘sea’ of electrons. ALUMINUM

3+ How does this arrangement account for metallic properties?

3+ Let’s look at malleability.

3+

3+

3+

3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+

3+

3+

3+

3+

3+

3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

The delocalized electrons are a constant presence, always holding 3+ The delocalized electrons are a constant presence, always holding together any shifting (+) ions. 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+

This is malleability. The delocalized electrons are a 3+ The delocalized electrons are a constant presence, always holding together any shifting (+) ions. 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ This is malleability. 3+ 3+

Why aren’t ionic crystals malleable?

Ionic crystals cleave because the like charges of shifted ions repel each other. The cleavage often results in a shear, smooth face between the split crystals.

Back to metallic crystals!

The strong attraction between the (+) ions in the crystal for the 3+ The strong attraction between the (+) ions in the crystal for the delocalized electrons results not only in malleability:

This structure makes metals hard and strong, with a high 3+ This structure makes metals hard and strong, with a high melting point:

This structure makes metals hard and strong, with a high 3+ This structure makes metals hard and strong, with a high melting point: The particles want to stay together!

In general, the more delocalized electrons, the tougher the metal. 3+ In general, the more delocalized electrons, the tougher the metal. Transition metals have the most delocalized electrons and are the strongest.

Delocalized electrons also carry electric current and heat 3+ Delocalized electrons also carry electric current and heat due to their ability to move through the crystal.

characteristic luster. 3+ AND delocalized electrons readily absorb and re-emit visible frequency photons, giving metals their characteristic luster.

TOO COOL!! The “Bean” in Chicago: 100% stainless steel—why so shiny?