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Ionic Bonds and Ionic Compounds

Ionic Bonds and Ionic Compounds. Forming Compounds from Ions. Objectives. When you complete this presentation, you will be able to … explain the electrical charge of an ionic compound. describe three properties of ionic compounds. Formation of Ionic Compounds: Introduction.

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Ionic Bonds and Ionic Compounds

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  1. Ionic Bonds and Ionic Compounds Forming Compounds from Ions

  2. Objectives • When you complete this presentation, you will be able to … • explain the electrical charge of an ionic compound. • describe three properties of ionic compounds.

  3. Formation of Ionic Compounds:Introduction • Ionic compounds are composed of a mixture of • cations(ions with positive charges) • anions(ions with negative charges) • Cations are usually metal ions. • Anions are usually nonmetal ions. • The compounds are usually electrically neutral.

  4. Formation of Ionic Compounds:Ionic Bonds • Cations and anions have opposite charges. • They are attracted to each other by electrostatic forces. • These forces are called ionic bonds.

  5. Formation of Ionic Compounds:Ionic Bonds • Bonds are formed by an exchange of electrons. • For example: • • • • • • • Na + Cl ➞ Na+ + Cl– • • • • • • • • • The NaCl formed is a neutral compound.

  6. Formation of Ionic Compounds:Ionic Bonds • Bonds are formed by an exchange of electrons. • For example: • • • • • • • • • • • • • • • Ca + Cl + Cl ➞ Ca2+ + Cl– + Cl– • • • • • • • • • • • • • • • • • The CaCl2 formed is a neutral compound.

  7. Formation of Ionic Compounds:Formula Units • Ionic compounds are composed of equal numbers of positive charges and negative charges. • NaCl • CaCl2

  8. Formation of Ionic Compounds:Formula Units • A chemical formulais meant to represent the kinds and numbers of atoms in the simplest representative unit of the compound. • For example: C6H12O6 indicates that there are six carbon atoms, twelve hydrogen atoms, and six oxygen atoms in the compound glucose. • For example: NaCl indicates that there is one sodium atom (ion) for each chloride atom (ion) in the compound of sodium chloride.

  9. Formation of Ionic Compounds:Formula Units • Ionic compounds (like sodium chloride) exist as large collections of ions (+ and –) and not as a collection of discrete molecules (like glucose). • This means that we use the lowest whole number ratio for the chemical formulas of ionic compounds. • These are called formula units.

  10. Properties of Ionic Compounds • Most ionic compounds are crystalline solids at room temperature. • For example: sodium chloride (NaCl) • For example: aragonite (CaCO3) • For example: rutile (TiO2) • Ionic compounds generally have high melting points.

  11. Properties of Ionic Compounds • Each ion in an ionic compound has a certain number of oppositely charged ions surrounding it. • That number is called the coordination number.

  12. Properties of Ionic Compounds • For example: In sodium chloride (NaCl), each Na+ is surrounded by six Cl– and each Cl– is surrounded by six Na+. • The coordination number of Na+ is six. • The coordination number of Cl– is six.

  13. Properties of Ionic Compounds • For example: In cesium bromide (CsBr), each Cs+ is surrounded by eight Br– and each Br– is surrounded by eight Cs+. • The coordination number of Cs+ is eight. • The coordination number of Br– is eight.

  14. Properties of Ionic Compounds • For example: In titanium dioxide (TiO2), each Ti4+ is surrounded by six O2– and each O2– is surrounded by three Ti4+. • The coordination number of Ti4+ is six. • The coordination number of O2– is three.

  15. Properties of Ionic Compounds • Ionic compounds are generally conductivewhen melted or dissolved in water. • When an ionic compound is melted • the orderly arrangement of ions is destroyed • the ions are free to migrate as they please • an electric voltage will cause the cations to migrate to one pole and the anions to migrate to the other pole.

  16. Properties of Ionic Compounds • Something similar happens when an ionic compound dissolves in water.

  17. Summary • Ionic compounds are composed of a mixture of cations(ions with positive charges) and anions (ions with negative charges) • Cations are usually metal ions and anions are usually nonmetal ions. • Ionic compounds are usually electrically neutral.

  18. Summary • Cations and anions are attracted to each other by electrostatic forces called ionic bonds. • Bonds are formed by an exchange of electrons. • Ionic compounds are composed of equal numbers of positive charges and negative charges.

  19. Summary • Cations and anions are attracted to each other by electrostatic forces called ionic bonds. • The chemical formulas for ionic compounds use the lowest whole number ratio for the chemical formulas of ionic compounds which are called formula units.

  20. Summary • Cations and anions are attracted to each other by electrostatic forces called ionic bonds. • Most ionic compounds are crystalline solids at room temperature. • Ionic compounds generally have high melting points.

  21. Summary • Each ion in an ionic compound has a certain number of oppositely charged ions surrounding it which is called the coordination number. • Ionic compounds are generally conductive when melted or dissolved in water.

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