Presentation is loading. Please wait.

Presentation is loading. Please wait.

C HAPTER 7 Ionic and Metallic Bonding. S ECTION 1 Ions.

Similar presentations


Presentation on theme: "C HAPTER 7 Ionic and Metallic Bonding. S ECTION 1 Ions."— Presentation transcript:

1 C HAPTER 7 Ionic and Metallic Bonding

2 S ECTION 1 Ions

3 L EARNING T ARGETS – I can determine the number of valence electrons in an atom of a representative element – I can explain how the octet rule applies to atoms of metallic and nonmetallic elements – I can describe how cations form – I can explain how anions form.

4 V ALENCE E LECTRONS Valence electrons – electrons in the highest occupied energy level of an elements atoms. Valence electrons determine an elements properties.

5 To find the number of valence electrons simply look at the group number. Helium is the only exception to this, only has 2 electrons. Electron dot structure – diagrams that show the valence electrons as dots.

6

7 T HE O CTET R ULE Octet rule – in forming compounds, atoms tend to achieve the electron configuration of noble gases. Or the configuration of n s 2 n p 6

8 Atoms of metallic elements tend to lose their valence electrons, leaving a complete octet in the next-lowest energy level. Atoms of nonmetallic elements tend to gain electrons or share electrons with another nonmetallic element to achieve a complete octet.

9 F ORMATION O F C ATIONS An atom’s loss of valence electrons produces a cation, or a positively charged ion. Usually metal atoms – very few nonmetals lose electrons.

10 Transition metals will achieve the most stable configuration possible so they may be exceptions to the octet rule. Also called a pseudo-noble gas electron configuration.

11 Which looks like

12

13 F ORMATION O F A NIONS The gain of negatively charged electrons by a neutral atom produces an anion. Nonmetals form anions and change their name endings to – ide. Halide ion – ions produced when atoms of chlorine and the other halogens gain electrons.

14 Which looks like

15

16

17 S ECTION 2 Ionic Bonds and Ionic Compounds

18 L EARNING T ARGETS – I can explain the electrical charge of an ionic compound – I can describe three properties of ionic compounds.

19 F ORMATION OF I ONIC C OMPOUNDS Ionic compound – compounds composed of cations and anions. Although they are composed of ions, ionic compounds are electrically neutral. Sodium reacting with chlorine 1 Sodium reacting with chlorine 2 Aluminum reacting with bromine Sodium reacting with bromine Aluminum reacting with iodine

20 I ONIC B ONDS Ionic bonds – electrostatic forces that hold ions together in ionic compounds. Think about sodium and chloride Sodium has 1 valence electron. Chlorine has 7 valence electron. When they combine sodium gives chlorine its 1 valence electron so they both satisfy the octet rule.

21

22 F ORMULA U NITS Chemical formulas – shows the kinds and numbers of atoms in the smallest representative unit of a substance. Formula unit – lowest whole-number ratio of ions in an ionic compound.

23 E XAMPLES : Look at sodium and oxygen

24 E XAMPLES : Look at aluminum and oxygen

25 E XAMPLES : Pick a metal from the representative elements. Pick a nonmetal from the representative elements

26 P ROPERTIES OF I ONIC C OMPOUNDS Most ionic compounds are crystalline solids at room temperature. Ionic compounds generally have high melting points.

27 Coordination number – number of ions of opposite charge that surround the ion in a crystal

28 Ionic compounds can conduct an electric current when melted or dissolved in water.

29 S ECTION 3 Bonding In Metals

30 L EARNING T ARGETS – I can model the valence electrons of metal atoms – I can describe the arrangement of atoms in a metal – I can explain the importance of alloys.

31 M ETALLIC B ONDS AND M ETALLIC P ROPERTIES The valence electrons of metal atoms can be modeled as a “sea” of electrons. Metallic bonds Metallic bonds – attraction of the free-floating valence electrons for the positively charged metal atoms.

32

33 M ETALLIC B ONDS AND M ETALLIC P ROPERTIES Good conductors of electrical current because of the free-floating electrons. Malleable (pounded into sheets) Ductile (pulled into wires)

34 C RYSTALLINE S TRUCTURE OF M ETALS Metal atoms are arranged in very compact and orderly patterns. Body-centered cubic (8 neighbors) Face-centered cubic (12 neighbors) Hexagonal close- packed (12 neighbors)

35 A LLOYS Alloy – mixtures composed of two or more elements at least one of which is a metal. Alloys are important because their properties are often superior to those of the component elements.

36 Substitutional alloy – components are about the same size and one replaces (substitutes) another. Interstitial alloy – components are different sizes and smaller fits into the spaces (intercies) of the larger.


Download ppt "C HAPTER 7 Ionic and Metallic Bonding. S ECTION 1 Ions."

Similar presentations


Ads by Google