IONIC COMPOUNDS

Sec 8.1 Forming Chemical Bonds The force that holds atoms together is a chemical bond Valence electrons are involved in chemical bonds

Elements tend to react to acquire the stable electron structure of a noble gas (octet rule)

Formation of Positive Ions Positive ions form when an atom loses one or more valence electrons in order to obtain a noble gas formation

A cation is a positive ion

Formation of Negative Ions Negative ions form when an atom gains one or more valence electrons in order to obtain a noble gas formation

An anion is a negative ion formed when an atom gains one or more valence electrons

1. a force that holds two atoms together 2. Atoms gain more stable electron configurations by losing or gaining electrons. 3. Noble gases are relatively unreactive because they have eight electrone I n their outermost energy level, which is a stable configuration. 4. Positive ions form when atoms lose valence electrons. Negative ions form when valence electrons are added to an atom.   5. a. gain 3 electrons (3- ion) or lose 5 electrons (5+ ion) b. gain 2 electrons (2- ion) c. lose 2 electrons (2+ ion) d. lose 1 electron (1+ ion) 6. Models should show that the calcium atom loses two electrons forming Ca+2 and the bromine atom gains one atom forming Br-

Section 8.2 The Formation and Nature of Ionic Bonds Formation of an Ionic Bond An ionic bond is usually between a metal cation and a non-metal anion http://www.youtube.com/watch?v=T40sM8-SXso&feature=fvwp&NR=1

Formation of an Ionic Bond The electrostatic force that holds oppositely charged particles together in an ionic compound is called an Ionic Bond http://www.youtube.com/watch?v=xTx_DWboEVs

Formation of an Ionic Bond Compounds that contain ionic bonds are called ionic compounds. Ionic bonds that occur between metals and the non metal oxygen are called oxides  

Formation of an Ionic Bond  Most other ionic compounds are called salts

Formation of an Ionic Bond In an ionic bond the number of electrons lost must equal the number of electrons gained, Consider Ca and F  

Formation of an Ionic Bond In an ionic bond the number of electrons lost must equal the number of electrons gained,  

Ionic Compounds

Ionic Compounds Binary Ionic Compounds- contain only two different elements (one metallic cation and one nonmetallic anion).

Ionic Compounds Most ionic compounds are binary MgO is binary, CaSO4 is not binary Why?

Properties of Ionic Compounds The chemical bonds that occur between the atoms in a compound determine many of the physical and chemical properties.

Crystal Lattice The strong attraction of positive and negative ions in an ionic compound result in a 3 dimensional geometric arrangement of particles called a crystal lattice.

Crystal Lattice

Melting point, Boiling Point, Hardness and Color Ionic compounds generally have high melting points and boiling points.

Electrolyte  An ionic compound whose aqueous solution conducts electric current is called an electrolyte

Lattice Energy   The formation of ionic compounds from positive and negative ions is always exothermic.

Lattice Energy If this amount of energy is added to an ionic compound, the bonds will break. The energy required to separate one mole of the ions of an ionic compound is referred to as the Lattice Energy

7. Na3N 10. Al2S3 8. Li2O 11. Cs2P 9. SrF2

12. the electrostatic attraction between oppositely charged ions 13. Ions form from electron transfer. Oppositely charge electrons attract. 14. exist as crystals, high BP and MP, hard, rigid, conductive when dissolved or molten but not solid. 15. Each ion is surrounded by oppositely charged ions. 16. It is the energy required to separate the ions of an ionic compound and is the energy given off when positive and negative ions attract. 17. As the ionic radius of the non-metallic ion increases, the melting point and lattice energy decrease. 18. SrCl2

Section 8.3 Names and Formulas of Ionic Compounds Formula Unit   The simplest ratio of the ions represented in an ionic compound.

Section 8.3 Names and Formulas of Ionic Compounds Monatomic Ion a one-atom ion, such as Mg+2 or Br-

Names and Formulas of Ionic Compounds Most transition metals and some of those 3A and 4A can form several different positive ions

Names and Formulas of Ionic Compounds   Oxidation Number The charge of a monatomic ion is its oxidation number. (sometimes called oxidation state)   

The oxidation numbers of ions are used to determine the formulas for the ionic compounds they form.

Writing Formulas Criss cross the oxidation numbers Reduce subscripts if possible

Polyatomic Ions Many ionic compounds contain polyatomic ions, which are ions made up of more than one atom. The charge given to a polyatomic ion applies to the entire group of atoms.

Polyatomic Ions The polyatomic ion acts as an individual ion. The chemical formula can be written following the same rules as monatomic ions

Polyatomic Ions If more than one polyatomic ion is needed, place parentheses around the ion and write the appropriate subscript outside the parentheses. EX Mg(ClO3)2

Naming Ionic Compounds   Rules: 1. Name the cation first and the anion second  2. Monoatomic cations use the element. 3. Monoatomic anions take their name from the root of the element name plus the suffix -ide.   4. Group 1A and 2A metals have only one oxidation number. Transition metals and metals on the right side of the periodic table often have more that one oxidation number. the name and chemical formula (written as a roman numeral in parentheses after the name of the cation). 5. If the compound contains a polyatomic ion, simply name the ion.

Naming Ionic Compounds   Rules: 1. Name the cation first and the anion second  2. Monoatomic cations use the element. 3. Monoatomic anions take their name from the root of the element name plus the suffix -ide.   4. Group 1A and 2A metals have only one oxidation number. Transition metals and metals on the right side of the periodic table often have more that one oxidation number. the name and chemical formula (written as a roman numeral in parentheses after the name of the cation). 5. If the compound contains a polyatomic ion, simply name the ion.

Naming Ionic Compounds   Rules: 1. Name the cation first and the anion second  2. Monoatomic cations use the element. 3. Monoatomic anions take their name from the root of the element name plus the suffix -ide.   4. Group 1 and 2 metals have only one oxidation number. Transition metals and metals on the right side of the periodic table often have more that one oxidation number. the name and chemical formula (written as a roman numeral in parentheses after the name of the cation). 5. If the compound contains a polyatomic ion, simply name the ion.

Old, classic or common nomenclature Suffix “ic” added to the Latin name of the element with the higher oxidation number. Suffix “ous” added to the Latin name of the element with the lower oxidation number.

Section 8.4 Metallic Bonds and  the attraction of a metallic cation for delocalized electrons  

Section 8.4 Metallic Bonds and Properties of Metals Electron Sea Model  proposes that all metal atoms in a metallic solid contribute their valence electrons to form a “sea of electrons” that are not held by any specific atom and can easilly move from one atom to the next.  

Section 8.4 Metallic Bonds and Properties of Metals    Delocalized Electrons  Because they are free to move, these electrons are called delocalized electrons.

Section 8.4 Metallic Bonds and Properties of Metals Metal alloys  Form when a metal is mixed with one or more other elements.

Section 8.4 Metallic Bonds and Properties of Metals    Metallic Bond   Electron Sea Model Delocalized Electrons Properties of metals Metal alloys 

24. NaNo3 27. K2CrO4 25. Ca(Clo3)2 28. MgCO3 26. Al2(CO3)3

29. sodium bromide 32. copper (II) nitrate 30. calcium chloride 33. silver chromate 31. potassium hydroxide

Hydrate Lab

Hydrate Lab

Barium Chloride di hydrate hygroscopic.