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Bonding - Atoms interact (with their electrons) to form compounds. Sodium Chlorine Three Kinds of Bonds: Ionic Metal (+) Nonmetal (-) Metal transfers electrons to make opposites attract. Nonmetal Nonmetal Covalent The sharing of electrons creates a strong bond. Metal electrons Metal Metal Metal Metal Metallic All electrons are shared in a “sea of electrons.” 2 3 Independent Practice Fill in the the blanks C - Covalent M - Metallic I - Ionic 4 To understand how bonding works, we need to understand electrons. Proton Positive Charge Neutron No Charge Electron Negative Charge ++ 5 Valence Electrons The electrons on the outer energy level of an atom How many valence electrons do each of these have? 3 5 2 6 5 1 4 1 6 2 1 H 1.0079 8 8 3 4 Li Be 6.941 9.012 11 12 Na Mg 22.990 24.305 19 20 K Ca 39.098 40.08 Do you remember what the atomic number represents? It is the number of protons & electrons. 2 He 4.003 5 6 7 8 9 10 B C N O F 10.811 12.011 14.007 15.999 18.998 1.0079 13 14 15 16 17 18 Al 26.982 Ne Si P S Cl Ar 28.086 30.974 32.066 35.453 39.948 7 1 H 1.0079 Energy Level 1 2 electrons fit How many valence electrons does hydrogen have? How many valence electrons does helium have? Fill in the periodic table on your paper. 2 He 4.003 Energy Level 2 8 electrons fit: 5 6 7 8 3 4 8 9 Li Be B C N O F 6.941 9.012 10.811 12.011 14.007 15.999 18.998 How many valence electrons do each of the elements above have? Fill in the periodic table on your paper. 10 Ne 1.0079 Energy Level 3 8 electrons fit 11 12 13 Na Mg 22.990 24.305 Al 26.982 14 15 9 16 17 18 Si P S Cl Ar 28.086 30.974 32.066 35.453 39.948 How many valence electrons do each of the elements above have? Fill in the periodic table on your paper. 10 Look at the periodic table. Do you notice a pattern? What is it? 11 1 2 You should have noticed that each column has the same number of valence electrons. This is true all the way down the periodic table: 3 4 5 6 7 8 12 But there is something you need to know about electrons and the energy levels where they live. Some are happier, more stable than others. You see, energy levels like to be FULL. These are “HAPPY” or “Stable” atoms. 2 He 10 Ne 1.0079 18 Ar 39.948 4.003 Which other atoms are FULL? Everyone wants to be happy-so, all atoms try to get happy. But alas, they cannot do it alone. They must find other atom friends to make them happy. But the right kind of friend is hard to find -- if you know what I mean. • • Someone that understands you. One who is willing to give you what you need most -a part of himself. 13 More on electrons: Atoms get happy (stable) by filling up their outer shell of electrons. Atoms with 4 or more valence electrons will not give them up! No, and don’t ask again! Which columns on the periodic table will NOT give away electrons? Atoms with less than 4 valence electrons are very generous. Yes, is there anything else? Which columns on the periodic table will give away electrons? 14 Even MORE about electrons: 15 However this affects their charge…Remember normally: Have the same # of Protons (+) = Electrons (-) If the the blue atom gives up an electron, it becomes (+). If the yellow atom gives up an electron, it becomes (-). Lose -e makes + Gain -e makes - 16 1 1+ H Because of this, we assign a group of elements an oxidation number. Compare this number to the valence electrons. 3 4 5 6 7 3+ 4 3- 2- 1- He 2 2+ Be 8 0 Write the oxidation numbers on your periodic table. B C N O F 17 Independent Practice Fill in the the chart on your paper. 18 Bonding An atom’s outer electron energy level is filled by either exchanging or sharing electrons. NH3 H N NaCl H Na Cl H 19 Ionic Bonds Metal to Nonmetal Electrons either taken or given away Sodium + Chlorine Opposites attract Ionic Bonds Metal to Nonmetal Sodium gives Chlorine 1 electron. Na Cl Sodium is happy at energy level 2. Chlorine is happy at energy level 3. Sodium NaCl Chlorine Sodium Chloride 20 Covalent 21 non-metal + nonmetal Nitrogen Electrons are shared. Hydrogen Hydrogen H NH3 Ammonia H Hydrogen N H 22 -e Ag+ -e metal metal metal Metallic Share in a sea of electrons -e Ag+ -e Ag+ -e Ag+ -e -e Ag+ -e Ag+ -e -e Ag+ Ag+ -e -e -e Ag+ 23 Independent Practice Fill in the the chart on your paper. 0 1+ 2+ When you combine atoms, 3+ 4 you use the oxidation numbers to help you figure out the ratio. 3- 2- 1- Oxidation Number Varies Simply switch the oxidation number to get the correct subscript. Put the #s in lowest terms if necessary. +2O-2 Mg1+2Cl-1 Mg 2 2 = 2 MgCl2 MgO Fe2+3 O-2 3 Fe2O3 24 25 Independent Practice Fill in the the chart on your paper. Polyatomic Compounds: 26 Compounds that Act as a Unit Charge 1+ 1111223- Mg+2 PO43 3 2 Mg3(PO4)2 Name Ammonium Acetate Chlorate Hydroxide Nitrate Carbonate Sulfate Phosphate Formula NH4+ C2H3O4ClO3 OHNO3CO32SO42PO43- Li+2 SO42 2 2 LiSO4 Fe+3 NO4-2 2 3 Fe2 (NO4)3 Note the ( ) on multiple polyatomic ions. 27 Independent Practice Fill in the the chart on your paper. Naming Compounds 28 Rules for naming binary (meaning 2 types of atoms) ionic compounds: Example: KBr 1. Write the name of the metal first. 2. Write the name of the nonmetal changing the ending to “ide.” Potassium Bromine Bromide 29 Independent Practice Fill in the blanks. Naming Compounds Rules for naming binary ionic compounds: (Binary means 2 types of atoms.) Example: CuCl 1. Write the name of the metal first. 2. Write the name of the nonmetal changing the ending to “ide.” 3. If the metal is a “transition metal,” the oxidation number varies. Therefore, to name the compound we must put the ionic charge in parentheses. For example: Copper (I) Chlorine Chloride because the oxidation of chlorine is 1. 30 31 Independent Practice Fill in the blanks. Naming Compounds Polyatomic Charge 1+ 1111223- Name Ammonium Acetate Chlorate Hydroxide Nitrate Carbonate Sulfate Phosphate Formula NH4+ C2H3O4ClO3 OHNO3CO32SO42PO43- Rules for naming polyatomic ionic compounds: 1. Write the name of the metal first. 2. Write the name of the polyatomic nonmetal from the chart. Example: K2 SO4 Potassium Sulfate 32 Naming Compounds 33 Ionic Rules for naming polyatomic ionic compounds: Charge 1+ 1111223- Name Ammonium Acetate Chlorate Hydroxide Nitrate Carbonate Sulfate Phosphate Formula NH4+ C2H3O4ClO3 OHNO3CO32SO42PO43- If the polyatomic ion is first, then: 1. Use the chart above to name the metal. 2. Write the name of the nonmetal changing the ending to “ide.” Example: NH4Cl Ammonium Chloride