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Chapter 7: Ionic and Metallic Bonding. Section 7.1: Ions.

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Presentation on theme: "Chapter 7: Ionic and Metallic Bonding. Section 7.1: Ions."— Presentation transcript:

1 Chapter 7: Ionic and Metallic Bonding

2 Section 7.1: Ions

3 Valence Electrons Electrons that are in the highest occupied energy level of an atom. Electrons that are in the highest occupied energy level of an atom. Mostly determine the chemical properties of an element Mostly determine the chemical properties of an element Valence electrons are usually the only electrons involved in a chemical bond. Valence electrons are usually the only electrons involved in a chemical bond.

4 How many valence electrons? Look at the family (or column) it is in on the Periodic Table. Look at the family (or column) it is in on the Periodic Table. Family 1 has 1 electron Family 1 has 1 electron Family 2 has 2 electrons…etc. Family 2 has 2 electrons…etc. NaNa HHe LiBeBCNOFNe NaMgAlSiPSClAr KCaGaGeAsSeBrKr RbSrInSnSbTeIXe CsBaTlPbBiPoAtRn or 2

5 Electron Dot Structure (a.k.a. Lewis Dot Diagram) How do you draw Electron Dot Structures? Write the element symbol. Write the element symbol. Determine what family it is in. Determine what family it is in.Na Then…put dots around the symbol to represent the valence electrons. Then…put dots around the symbol to represent the valence electrons. NaNa

6 Practice these: BNe

7 The Octet Rule Atoms tend to gain or lose electrons to achieve the electron configuration of a noble gas (8 e - ) Atoms tend to gain or lose electrons to achieve the electron configuration of a noble gas (8 e - ) Noble gas configuration is 8 electrons in its highest orbital: Noble gas configuration is 8 electrons in its highest orbital: ns 2 np 6 ns 2 np 6 Exception is H and He: only 2 electrons to fill highest orbital Exception is H and He: only 2 electrons to fill highest orbital

8 Cations Definition: A positively charged ion. Definition: A positively charged ion. Cation Cation Has a + sign in word. Has a + sign in word. Cation is an atom that has LOST electrons. Cation is an atom that has LOST electrons. Naming: Naming: element name (NO change) element name (NO change) Add word “ion” Add word “ion”

9 Examples of Cations Li +1 Li +1 Lithium ion Lithium ion Na +1 Na +1 Sodium ion Sodium ion Mg +2 Mg +2 Magnesium ion Magnesium ion

10 Anions Definition: A negatively charged ion. Definition: A negatively charged ion. Anion Anion Letter “A” has negative sign Letter “A” has negative sign Anion is an atom that has GAINED electrons. Anion is an atom that has GAINED electrons. Naming: Naming: Change end of element to ”-ide” Change end of element to ”-ide” Add word “ion” Add word “ion”

11 Examples of Anions Br -1 Br -1 Bromide ion Bromide ion O -2 O -2 Oxide ion Oxide ion Cl -1 Cl -1 Chloride ion Chloride ion

12 Section 7.2: Ionic Bonds and Ionic Compounds

13 Review… Magnesium # of valence electrons # of valence electrons2 Gain or lose to achieve octet? Gain or lose to achieve octet? lose 2 Most stable ion formed: Most stable ion formed: Mg +2 Cation or Anion? Cation or Anion? Positive, so it’s a cation Positive, so it’s a cation

14 Ionic Compounds: Ionic Compounds: Compounds made up of metal cation and nonmetal anions. Compounds made up of metal cation and nonmetal anions.

15 Ionic Bonds Ionic Bonds The electrostatic force that holds ions together. The electrostatic force that holds ions together. Positive cations and negative anions attract each other. Positive cations and negative anions attract each other.

16 Chemical formula: Chemical formula: Shows the number and kinds of elements in a compound. Shows the number and kinds of elements in a compound. Always written with symbols and subscripts. Always written with symbols and subscripts. For example: For example: Li 2 O Li 2 O NaCl NaCl H 2 SO 4 H 2 SO 4

17 Electron Dot Structure and Ionic Bonds Sodium and Iodine Sodium and Iodine

18 Naming Ionic Compounds 3 rules: 3 rules: 1)Name of cation stays the same. 2)Change the end of the anion to “- ide” 3)If there is a polyatomic ion, the name doesn’t change. (see chart on page 192)

19 Electron Dot Structure and Ionic Bonds Magnesium and Sulfur Magnesium and Sulfur

20 Electron Dot Structure and Ionic Bonds Potassium and Phosphorus Potassium and Phosphorus

21 Electron Dot Structure and Ionic Bonds Aluminum and Oxygen Aluminum and Oxygen

22 Properties of Ionic Compounds Crystalline solids at room temperature. Crystalline solids at room temperature. Generally have a high melting point (the elements are highly attracted to each other so they are hard to separate). Generally have a high melting point (the elements are highly attracted to each other so they are hard to separate). They conduct an electric current when melted or dissolved. They conduct an electric current when melted or dissolved.


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