6.1 Ionic Compounds: (Pages )

Learning Goals I can explain how ions and ionic compounds are formed. I can describe the properties of ionic compounds.

Ions and Ionic Compounds The formation of ions involves the loss or gain of electrons. The ions formed by an atom will depend on its atomic structure and the number of valence electrons. Ionic compounds form when there is a transfer of electrons between atoms. An ionic bond is the attraction that keeps positive ions and negative ions together.

Characteristics of Ionic Componds Most ionic compounds are composed of a metal and a non-metal. Ionic compounds have high melting points and tend to be soluble in water. Ionic compounds are good electrical conductors when liquid or when dissolved in water.

Forming Ions: 1.What is an ion? An ion is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a positive or negative charge

2. Diagrams of Ions Lithium: [ Li ] + Neutral Atom Ion Symbol 3P 4N 3P 4N

3. How ionic compounds are formed When an ionic compound is formed, one or more electrons from one atom are transferred to another atom.

4. If an atom loses an electron, what kind of particle does it become? Once an atom loses one or more electrons, it becomes a positively charged ion. Once an atom gains one or more electrons, it becomes a negatively charged ion.

Ionic Compound Formation VIDEO: NaCl Formation -

Ionic Compound Formation

5. Properties of ionic compounds: PropertyDescription Physical States Exist in a solid arrangement called a crystal lattice (a regular repeating pattern of ions) Liquid version = aqueous state (solution) Gaseous version = non-existent EXAMPLE: Sodium Chloride (Salt)

PropertyDescription SolubilitySoluble in water The water separates the positive and negative ions from each other causing the bonds to break EXAMPLE: Salt dissolving in H 2 0 ConductivityIf solid – poor conductor (ions locked in place) If liquid – good conductor (ions free to move around) EXAMPLE: Salt vs. Salt water Water, Salt, Light!

6. Pros and Cons of Road Salt, an Ionic Compound Road salt is used in the winter to reduce icy driving conditions. Salt enters the environment through the soil, ground water and surface water ↑ levels of salt in soil can prevent/slow plant growth which can affect animals In water, ↑ levels of salt can affect aquatic plant and animal species

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