Chemical Bonding and Nomenclature. By Paul Surko New Dimensions High School Poinciana, FL

Transcription

1 Chemical Bonding and Nomenclature By Paul Surko New Dimensions High School Poinciana, FL

2 November 30, 2016 Please hold on to bonding worksheets from yesterday If I have yet to sign your SMART goals please turn them in along with your syllabus if I haven t received it. We have a lot to review today, in order to do it I need your help! Friday cometh..ready or not! Bellwork: 1. What do you need from me in order to succeed in this class? 2. What charge do atoms in group 1A and 7A take? What type of bond do they make? How do you know? 3. When would it be appropriate to draw a lewis structure? 4. How many electrons do ALL atoms want?

3 s Chemical Bond 8 I want you to meet a friend of mine? Bonding, the way atoms are attracted to each other to form molecules, determines nearly all of the chemical properties we see. And, as we shall see, the number 8 is very important to chemical bonding.

4 5.1 What are Molecules? Molecules are a combination of atoms bonded together. Bonding determines the chemical properties of the molecule (compound).

5 5.5 Ionic Bonding-Being Like the Noble Gases All atoms want to have the same number of electrons as the Noble Gases. The Noble Gases have very stable electron configurations. In order to achieve the same electron configuration as the Noble Gases metal atoms will give up electrons to form positive ions (cations) and non-metal atoms will receive or take additional electrons to become negative ions (anions). IONS are charged particles. Na becomes Na + Mg becomes Mg +2 Al becomes Al +3 Cl becomes Cl - O becomes O -2 N becomes N -3 The positive and negative ions are attracted to each other electrostatically.

6 Opposites Attract!

7 Putting Ions Together Na + + Cl - = NaCl Ca +2 + O -2 = CaO Ca +2 + Cl - = CaCl 2 Na + + O -2 = Na 2 O Al +3 + S -2 = Al 2 S 3 Ca +2 + N -3 = Ca 3 N 2 You try these! Li + + Br - = LiBr Mg +2 + F - = MgF 2 Al +3 + I - = AlI 3 NH PO -3 4 = (NH 4 ) 3 PO 4 Sr +2 + P -3 = Sr 3 P 2 K + + Cl - = Not NH KCl 43 PO 4

8 December 1, What is your favorite holiday tradition (or winter tradition if you do not celebrate Christmas)? 2. Draw the Lewis Structure for carbon disulfide 3. Write the chemical formula for Magnesium Bromide

9 5.2 The Covalent Bond Atoms can form molecules by sharing electrons in the covalent bond. This is done only among non-metal atoms.

10 5.3 Dot Structures-Octet Rule (All atoms want 8 electrons around them.) Valence electrons are those in the outermost orbitals. They are the ones that can form bonds. Lewis came up with a way to draw valence electrons so that the bonding could be determined.

11 Rules to Write Dot Structures 1. Write a skeleton molecule with the lone atom in the middle (Hydrogen can never be in the middle) 2. Find the number of electrons needed (N) (8 x number of atoms, 2 x number of H atoms) 3. Find the number of electrons you have (valence e - 's) (H) 4. Subtract to find the number of bonding electrons (N-H=B) 5. Subtract again to find the number of non-bonding electrons (H-B=NB) 6. Insert minimum number of bonding electrons in the skeleton between atoms only. Add more bonding if needed until you have B bonding electrons. 7. Insert needed non-bonding electrons around (not between) atoms so that all atoms have 8 electrons around them. The total should be the same as NB in 5 above.

12 1.S H O H Let's Try it! Water H 2 O 2.N 3.H 4.B 5.NB 6.E 2 x 2 = 4 for Hydrogen 1 x 8 = 8 for Oxygen 4+8=12 needed electrons 2 x 1 = 2 for Hydrogen 1 x 6 = 6 for Oxygen You have 8 available electrons 12-8 = 4 bonding electrons 8 4 = 4 non-bonding electrons.. H:O:H N 8 H 4 B 4 NB H:O:H.. H:O:H

13 1.S 2.N 3.H 4.B 5.NB 6.E.. H H:N:H Let's Try it! H H N H Ammonia NH 3 3 x 2 = 6 for Hydrogen 1 x 8 = 8 for Nitrogen 6+8=14 needed electrons 3 x 1 = 3 for Hydrogen 1 x 5 = 5 for Nitrogen You have 8 available electrons 14-8 = 6 bonding electrons 8 6 = 2 non-bonding electrons N 8 H 6 B 2 NB H.. H:N:H.. H H:N:H

14 Let's Try it! 1.S 2.N 3.H 4.B O C O Carbon Dioxide CO 2 1 x 8 = 8 for Carbon 2 x 8 = 16 for Oxygen 8+16=24 needed electrons 1 x 4 = 4 for Carbon 2 x 6 = 12 for Oxygen You have 16 available electrons = 8 bonding electrons N 16 H 8 B 8 NB 5.NB 16 8 = 8 non-bonding electrons O::C::O 6.E.... O::C::O.... O::C::O

15 1.S 2.N 3.H 4.B 5.NB 6.E.... :O:.... O::C: O: Let's Try it! O O C O Carbonate CO x 8 = 24 for Oxygen 1 x 8 = 8 for Carbon 24+8=32 needed electrons 3 x 6 = 18 for Oxygen 1 x 4= 4 for Carbon You have more available e - 's = 8 bonding electrons 24 8 = 16 non-bonding electrons N 24 H 8 B 16 NB O.. O::C:O.... :O:.... O::C: O:

16 December 2, 2016 Have your two worksheets out in front of you! Free write Friday write about whatever you want and then turn in your bellwork When you re finished we ll try a ticket out..or in.lol the website is socrative.com and my room name is andie7216

17 5.6 Polarity-Unequal Sharing of Electrons Even though all atoms want the same number of electrons as the Noble Gases, some want to get or give them more than others. The magnitude of this attraction for electrons is called Electronegativity. The more electronegative an atom is, the more it wants the electrons. Some atoms want to gain electrons so bad, they take them altogether to form negative ions. Some want to lose them so bad that they become positive ions.

18 Examples of Polar and Non- Polar Compounds HCl The Chlorine wants the electrons more than the Hydrogen. Thus we have +δ HCl -δ. NaCl Since Na is a metal it gives up its electron to form Na + and Cl takes the electron completely to form Cl -. Cl 2 (Cl Cl) The Chlorine molecules want the electrons equally so they form a non-polar molecule with NO partial or full charges. H 2 O Water is a bent molecule. The lone pair of electrons from the Lewis structure distorts its shape and it becomes a very polar molecule :O:H O::C::O H CO 2 Carbon Dioxide is a linear molecule. It has no lone pairs of electrons from the Lewis structure. The two oxygen atoms pull equally and make it a non-polar molecule.

19 5.7 Nomenclature Naming of Compounds Binary Compounds have two types of atoms (not diatomic which has only two atoms). Metals (Groups I, II, and III) and Non-Metals Metal Sodium + Non-Metal ide Chlorine Sodium Chloride NaCl Metals (Transition Metals) and Non-Metals Metal Iron +Roman Numeral ( ) III + Non-Metal ide Bromine Iron (III) Bromide FeBr 3 Compare with Iron (II) Bromide FeBr 2

20 5.7 Nomenclature Naming of Compounds Binary Compounds have two types of atoms (not diatomic which has only two atoms). Metals (Transition Metals) and Non-Metals Older System Metal (Latin) Ferrous + ous or ic + Non-Metal ide Bromine Ferrous Bromide FeBr 2 Compare with Ferric Bromide FeBr 3 Non-Metals and Non-Metals Use Prefixes such as mono, di, tri, tetra, penta, hexa, hepta, etc. CO 2 Carbon dioxide CO Carbon monoxide PCl 3 Phosphorus trichloride CCl 4 Carbon tetrachloride

21 Let s Practice! CaF 2 K 2 S CoI 2 SnF 2 SnF 4 OF 2 CuI 2 CuI SO 2 SrS LiBr Name the following. Calcium Flouride Potassium Sulfide Cobalt (II) Iodide or Cobaltous Iodide Tin (II) Flouride or Stannous Flouride Tin (IV) Flouride or Stannic Flouride Oxygen diflouride Copper (II) Iodide or Cupric Iodide Copper (I) Iodide or Cuprous Iodide Sulfur dioxide Strontium Sulfide Lithium Bromide

22 Acids (with H in front) Binary acids (without oxygen in formula) Hydro ic Acid HCl Hydrochloric acid HBr Hydrobromic acid Oxy acids (with oxygen in formula) -ate goes to ic and ite goes to -ous HNO 3 Nitric acid HNO 2 Nitrous acid H 2 SO 4 Sulfuric acid H 2 SO 3 Sulfurous acid H 3 PO 4 Phosphoric acid H 3 PO 3 Phosphorous acid

23 Lets Practice! HF Na 2 CO 3 H 2 CO 3 KMnO 4 HClO 4 H 2 S NaOH CuSO 4 PbCrO 4 H 2 O NH 3 Hydroflouric acid Sodium carbonate Carbonic acid Potassium permanganate Perchloric acid Hyrdogen sulfuric acid Sodium hydroxide Copper (II) sulfate or Cupric sulfate Lead (II) chromate or Plubous chromate Hydrooxic acid (no just water) Nitrogen trihydride (no..just ammonia)

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