Ionic Bonds Covalent Bonds Metallic Bonds

Transcription

1 Unit 5 Bonding

2 Types of Bonds Ionic Bonds Covalent Bonds Metallic Bonds -Usually between a metal and a nonmetal -Electrolytes only when dissolved in water (aqueous) or melted as a liquid, NOT as a SOLID! -Difference in electronegativity between the metal & nonmetal is greater than 1.7 -High melting pt/ boiling pt -Hard/ crystal structure

3 Types of Bonds Ionic Bonds Covalent Bonds Metallic Bonds -Usually between a metal and a nonmetal -Electrolytes only when dissolved in water (aqueous) or melted as a liquid, NOT as a SOLID! -Difference in electronegativity between the metal & nonmetal is greater than 1.7 -High melting pt/ boiling pt -Hard/ crystal structure -Usually between 2 nonmetals -Non- electrolytes -Low melting pt/ boiling pt -Soft

4 Types of Bonds Ionic Bonds Covalent Bonds Metallic Bonds -Usually between a metal and a nonmetal -Electrolytes only when dissolved in water (aqueous) or melted as a liquid, NOT as a SOLID! -Difference in electronegativity between the metal & nonmetal is greater than 1.7 -High melting pt/ boiling pt -Hard/ crystal structure -Usually between 2 nonmetals -Non- electrolytes -Low melting pt/ boiling pt -Soft - Metals only -Alloys mixture of metals -Malleable/Ductile/Luster -Conductive as a SOLID & LIQUID -High melting pts (generally)

5 Lewis Dot Diagrams Reflect: Why do atoms gain, lose, or share electrons?

6 Lewis Dot Diagrams Ionic Bonds Covalent Bonds Metallic Bonds - Between a metal and a nonmetal -Valence electrons are TRANSFERRED from the metal to the nonmetal -Resulting ions (+ and - ) ions are attracted to each other by electrostatic attraction.

7 Ionic Bonding

8 Lewis Dot Diagrams Ionic Bonds Covalent Bonds Metallic Bonds - Between a metal and a nonmetal -Valence electrons are TRANSFERRED from the metal to the nonmetal -Resulting ions (+ and - ) ions are attracted to each other by electrostatic attraction. -Between nonmetals -Valence electrons are SHARED between the nonmetals -Results in a MOLECULE (covalent substances are called molecular substances) -Single bonds (sharing 2 e- ), double bonds (sharing 4 e-), triple bonds (sharing 6 e- ) are possible

9 Covalent Bonding ww

10 Lewis Dot Diagrams Ionic Bonds Covalent Bonds Metallic Bonds - Between a metal and a nonmetal -Valence electrons are TRANSFERRED from the metal to the nonmetal -Resulting ions (+ and - ) ions are attracted to each other by electrostatic attraction. -Between nonmetals -Valence electrons are SHARED between the nonmetals -Results in a MOLECULE (covalent substances are called molecular substances) -Single bonds (sharing 2 e- ), double bonds (sharing 4 e-), triple bonds (sharing 6 e- ) are possible -Valence electrons are MOBILE, no ties to any specific nucleus/atom - sea of mobile electrons -Results in a highly malleable, ductile, conductive substance -Examples: Iron, zinc, tin, copper, etc.

11 Metallic Bonding y/resource/animations/metallic_bond/metalli c.html

12 Lewis Dot Diagrams * Remember that Lewis dot diagrams show valence electrons only.

13 Ionic Bonds Examples: KBr:

14 Ionic Bonds Examples: Potassium and Bromine:

15 Ionic Bonds Examples: Li 2 O:

16 Ionic Bonds Examples: Lithium and Oxygen:

17 Ionic Bonds Examples: Al 2 O 3 :

18 H 2 O: Covalent Bonds

19 NH 3 Covalent Bonds

20 F 2 Covalent Bonds

21 Cl 2 Covalent Bonding

22 CO 2 Covalent Bonding

23 HCl Covalent Bonding

24 H 2 S Covalent Bonding

25 CH 4 Covalent Bonding

26 N 2 Covalent Bonding

27 PH 3 Covalent Bonding

28 O 2 Covalent Bonding

29 Metallic Bonds

30 Additional Bonding Information 1. Network Covalent Bonding: Atoms are covalently bonded in a giant structure Interconnected atoms gives network solids strength, high melting points and NO conductivity Most common in silicon & Carbon/ grp 14 compounds, diamonds and quartz

31 Additional Bonding Information 2. Allotropes Same element bonded in different patterns. -different structure = different properties Carbon: -graphite (loose 2-D sheets) -charcoal (no pattern) -diamond (network covalent) -Fullerenes (large hollow spheres) Oxygen: -O 2 (gaseous oxygen) -O 3 (ozone)

32 Additional Bonding Information 3. Structure: Crystalline: Ordered structure Amorphous: Unordered structure

33 Additional Bonding Information Ionic compounds that have trapped water in the lattice For example: CuSO 4 5H 2 O means that for every CuSO 4, there are five water molecules trapped in the lattice

34 Additional Bonding Information 5. Hydration: Ions become surrounded by water molecules when dissolved (hydration surrounded by a sphere of water).

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36 Writing Formulas Ions: Atoms that have lost or gained electrons to achieve a complete valence shell. Ex: Al +3 O -2

37 Cation: A positively charged ion (lost e-) Writing Formulas Anion: Negatively charged ion (gained e-)

38 Polyatomic Ions: Ions made of mare than one atom (found on Table E). The ion is held together by covalent bonds. The resulting compound has ionic properties. Writing Formulas

39 Writing Formulas

40 Writing Formulas

41 Naming Compounds

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43 Naming Compounds

44 Naming Compounds

45 Ionic Formulas To write ionic formulas from names: You have to write the ions but make sure they balance!! For example: calcium chloride = Ca and Cl, but since Ca loses 2 e- and Cl gains 1 e - = CaCl 2 Use parenthesis if you need more than one polyatomic ion from table E

46 Ionic Formulas Roman Numerals: Indicate the charges on elements that can have more than one possible charge. Ex: Iron (II) Bromide Copper (I) Chloride

47 Criss-cross method: 1. Write the charges on each ion 2. Criss-cross absolute value of charge 3. Omit 1 s, reduce charges if necessary Ionic Formulas

48 Write the Formulas for the Following: Sodium fluoride: Iron (III) Chloride: Potassium Oxide: Silver Iodide

49 Write the Formulas for the Following: Magnesium Oxide: Aluminum Sulfide: Barium Oxide: Lead (IV) Sulfide:

50 Ionic Formulas Polyatomic Ions: Ions that consist of more than one type of atom covalently bonded. Ex: NO 3-1, SO 4-2, NH 4 +1 All polyatomic ions are listed on Table E in your Reference Tables.

51 Ionic Formulas Hint: The criss cross method can be used to write ionic formulas with polyatomic ion. Name of Ionic Compound Ions and Charges that make up the compound Ionic Formula Lithium Nitrate Sodium Sulfate Aluminum Sulfate Calcium Carbonate Barium Nitrate

52 Naming Ionic Compounds Reflect: Why are ionic compounds always composed of a positive (metal) and negative (nonmetal) ion?

53 Naming Ionic Compounds

54 Practice Naming KBr: AlBr 3 : Na 2 CO 3 :

55 Practice Naming: Li 2 O: NH 4 NO 3 : BeS:

56 Naming Ionic Formulas Roman Numerals: Indicate the charge on a metal (used for the metals with more than one possible charge). You MUST include roman numerals for: Lead (Pb), Tin (Sn), & transition metals EXCEPT for two atoms: Zinc (Zn) = +2 Silver (Ag) = +1

57 Naming Ionic Compounds To determine the roman numeral:

58 Examples: Name the following CuSO 4 Fe(NO 3 ) 3 Cu 2 O

59 Examples: Name the following AgNO 3 MnCl 4 TiBr 2

60 Electrolytes & Ionic Compounds Ionic Substances: Electrostatic attraction between a positive and negative ion.

61 Electrolytes & Ionic Compounds Ionic Solids Crystal Lattice: Solid structure of alternating + and ions.

62 Lewis Dot Diagrams and Ionic Compounds Dissolved ions in water Ions become surrounded by water molecules when dissolved (hydration surrounded by a sphere of water).

63 Lewis Dot Diagrams and Ionic Compounds Electrolytes: substance that conducts electricity when dissolved in aqueous solution Requires: mobile, charged particles (ions).

64 Lewis Dot Diagrams and Ionic Compounds Examples of substances that conduct electricity (are electrolytes): Salt Solutions: NaCl, Zn(SO 4 ) 2 Acids: HCl, vinegar, fruit juice Bases: NaOH

65 Crystal Lattice/Ionic Compound: Composed of a structure of (+) and (-) ions that minimize repulsion and increase attraction.

66 Ionic Formulas & Hydrates Hydrates: Ionic compounds that have trapped water in the crystal lattice of an ionic compound. For example: CuSO 4 5H 2 O means that for every CuSO 4 there are 5 water molecules trapped in the lattice. To name: add a prefix and hydrate to the end (mono, di, tri, tetra, penta, hexa, hepta, octa,etc)

67 Ionic Formulas & Hydrates CuSO 4 5H 2 O BaCO 3 3H 2 O NaNO 3 7H 2 O

68 Covalent Compounds Reflect: Covalent bonding involves sharing electrons. What type of elements would share electrons?

69 Covalent Compounds COVALENT BONDING 2 atoms share one pair of electrons One electron is shared by each for a total of 2 electrons Generally between 2 nonmetals Electronegativity difference less than 2 Covalent bonds create molecules Soft, low melting point & boiling point, bad conductors of heat & electricity, exist as a solid, liquid or a gas. Can be single ( 2 shared e-), double ( 4 shared e-) or triple covalent bond ( 6 shared e-)

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71 Covalent Bonding Drawing covalent bonds with Lewis dot structures: 1. Each atom wants a full octet (remember that 1 st level = 2 electrons) 2. Every bond is two electrons one from each atom Example: F 2

72 Reflect: Naming Covalent Compounds Identify the identity (covalent, ionic, or both) of each: CaO NO 2 MgSO 4 HBr PCl 3 NH 4 Cl

73 Naming Covalent Compounds Naming Covalent Compounds: Uses prefixes to indicate the number and type of each atom 1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexta 7 = hepta 8 = octo 9 = non 10 = deca Still put ide on ending You can drop the mono- prefix on the first atom only

74 Naming Covalent Compounds Name the following N 2 O 4: BF 3: NO 2:

75 Naming Covalent Compounds Name the following PCl 5: P 2 O 3: CO:

76 Naming Covalent Compounds Write the Formulas: Carbon tetraiodide: Dihydrogen monosulfide: Dihydrogen monoxide: Nitrogen trinydride:

77 Metallic Bond: Metallic Solids Created with metallic atoms: fixed positive cations with free electrons flowing around them sea of mobile electrons Collective in nature not between just one or two atoms Results in metals having malleability, ductility, strength, thermal and electrical conductivity, and luster

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