5 Ionic Solids Structure and Properties a Formula

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5. Ionic Solids, Structure and Properties a. Formula Units The smallest part of an

5. Ionic Solids, Structure and Properties a. Formula Units The smallest part of an ionic compound that has all the properties of that compound is called a formula unit.

Ionic Compounds • Have high melting points due to large electrostatic attraction, and are

Ionic Compounds • Have high melting points due to large electrostatic attraction, and are not volatile. • Are brittle will shatter or cleave when struck • Conduct electricity when dissolved or molten (liquid) • Binary (2 elements) compounds have “-ide” as a subscript when naming. – IONS move to conduct electricity

For example, for the compound sodium chloride, Na. Cl, a model of a formula

For example, for the compound sodium chloride, Na. Cl, a model of a formula unit would be Na 1+ Cl 1 -

For example, for the compound potassium sulfide, K 2 S, a model of a

For example, for the compound potassium sulfide, K 2 S, a model of a formula unit would be K 1+ S 2 K 1+

For example, for the compound chromium(III) fluoride, Cr. F 3, a model of formula

For example, for the compound chromium(III) fluoride, Cr. F 3, a model of formula unit would be F 1 - Cr 3+ F 1 -

5. Ionic Solids, Structure and Properties b. Crystals An ionic crystal is a large

5. Ionic Solids, Structure and Properties b. Crystals An ionic crystal is a large collection of formula units in a an alternating array of positive and negative ions. The positions that the ions occupy and that determine the observable shape of the crystal are called the lattice points.

Formula Unit Na 1+ Cl 1 - Ionic Bond Between The Ions Formula Unit

Formula Unit Na 1+ Cl 1 - Ionic Bond Between The Ions Formula Unit Na 1+ Cl 1 - Electrostatic Attraction Positive-Negative Attraction Between the Formula Units

Sodium Chloride Crystal Na 1+ Cl 1 Cl 1 - Na 1+ Cl 1

Sodium Chloride Crystal Na 1+ Cl 1 Cl 1 - Na 1+ Cl 1 - Na 1+ Cl 1 - Na 1+ Cl 1 - Na 1+

5. Ionic Solids c. Properties - generally hard - but can be cleaved or

5. Ionic Solids c. Properties - generally hard - but can be cleaved or broken - low volatility - high melting and boiling points - do not conduct electricity in the solid state - does conduct electricity when melted or when placed in water

Strong Electrostatic Forces Na 1+ Cl 1 - Na 1+ Cl 1 Crystal cleaves

Strong Electrostatic Forces Na 1+ Cl 1 - Na 1+ Cl 1 Crystal cleaves and forms a flat surface. Cl 1 - Na 1+ Cl 1 - Na 1+

Strong Electrostatic Forces Na 1+ Cl 1 - Like Charges Repel 1+ 1 Crystal

Strong Electrostatic Forces Na 1+ Cl 1 - Like Charges Repel 1+ 1 Crystal Shatters Na Cl Na 1+ Cl 1 - Na 1+

Ionic solids do not readily sublime due to the strong electrostatic attractions. Na 1+

Ionic solids do not readily sublime due to the strong electrostatic attractions. Na 1+ Cl 1 - Na 1+ Room temperature Na 1+ Cl 1 - Na 1+

Ionic solids can be melted but much heat is required due to the strong

Ionic solids can be melted but much heat is required due to the strong electrostatic attractions. Na 1+ Cl 1 - Na 1+ D Na 1+ Cl 1 - Melting produces freely mobile ions.

Solid ionic crystals are nonelectrolytes, that is, they do not conduct electricity. Na 1+

Solid ionic crystals are nonelectrolytes, that is, they do not conduct electricity. Na 1+ Cl 1 - Na 1+ D Na 1+ Cl 1 - Melting produces freely mobile ions. Moving charged particle do conduct electricity. Molten ionic solids are electrolytes.

H O H O H Na 1+ Cl 1 - Na 1+ H O

H O H O H Na 1+ Cl 1 - Na 1+ H O H Cl 1 - Na 1+ Cl 1 - O H H H O H H Na 1+ Cl 1 - Na 1+ Dissolving produces freely mobile ions. Moving charged particle do conduct electricity. Soluble ionic solids are electrolytes. H Solid ionic crystals are nonelectrolytes, that is, they do not conduct electricity.