Presentation on theme: "Chemical Bonding and Nomenclature Chemical Bonding and Nomenclature By Paul Surko New Dimensions High School Poinciana, FL."— Presentation transcript:
Chemical Bonding and Nomenclature Chemical Bonding and Nomenclature By Paul Surko New Dimensions High School Poinciana, FL
s 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.
5.1 What are Molecules? Molecules are a combination of atoms bonded together. Bonding determines the chemical properties of the molecule (compound).
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. N becomes N -3 Al becomes Al +3 Cl becomes Cl - O becomes O -2 Mg becomes Mg +2 Na becomes Na + The positive and negative ions are attracted to each other electrostatically.
Putting Ions Together Na + + Cl - = NaCl Ca +2 + O -2 = CaONa + + O -2 = Na 2 O Al +3 + S -2 = Al 2 S 3 Ca +2 + N -3 = Ca 3 N 2 Ca +2 + Cl - = CaCl 2 You try these! Mg +2 + F - = NH PO 4 -3 = K + + Cl - = Al +3 + I - = Sr +2 + P -3 = Li + + Br - = Sr 3 P 2 AlI 3 MgF 2 (NH 4 ) 3 PO 4 KCl LiBr Not NH 43 PO 4
5.2 The Covalent Bond Atoms can form molecules by sharing electrons in the covalent bond. This is done only among non-metal atoms.
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.
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.
Let's Try it! 1. S 2. N 3. H 4. B 5. NB 6. E.. H:O:H H O H Water H 2 O 2 x 2 = 4 for Hydrogen 1 x 8 = 8 for Oxygen 4+8=12 needed electrons 8 – 4 = 4 non-bonding electrons 2 x 1 = 2 for Hydrogen 1 x 6 = 6 for Oxygen You have 8 available electrons = 4 bonding electrons 8 H 12 N 4 B 4 NB - - H:O:HH:O:H.. H:O:H
Let's Try it! 1. S 2. N 3. H 4. B 5. NB 6. E.. H:N:H H H N H Ammonia NH 3 3 x 2 = 6 for Hydrogen 1 x 8 = 8 for Nitrogen 6+8=14 needed electrons 8 – 6 = 2 non-bonding electrons 3 x 1 = 3 for Hydrogen 1 x 5 = 5 for Nitrogen You have 8 available electrons = 6 bonding electrons 8 H 14 N 6 B 2 NB H:N:H.. H:N:H H H H
Let's Try it! 1. S 2. N 3. H 4. B 5. NB 6. E.. O::C::O O C O Carbon Dioxide CO 2 1 x 8 = 8 for Carbon 2 x 8 = 16 for Oxygen 8+16=24 needed electrons 16 – 8 = 8 non-bonding electrons 1 x 4 = 4 for Carbon 2 x 6 = 12 for Oxygen You have 16 available electrons = 8 bonding electrons 16 H 24 N 8 B 8 NB - - O::C::O.... O::C::O
Let's Try it! 1.S 2.N 3.H 4.B 5.NB 6.E O::C: O: O O C O Carbonate CO x 8 = 24 for Oxygen 1 x 8 = 8 for Carbon 24+8=32 needed electrons 24 – 8 = 16 non-bonding electrons 3 x 6 = 18 for Oxygen 1 x 4= 4 for Carbon You have more available e - 's 24 H 32 N 8 B 16 NB O::C:O O::C: O: O.. :O: = 8 bonding electrons -2
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.
Examples of Polar and Non- Polar Compounds 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. NaCl Since Na is a metal it gives up its electron to form Na + and Cl takes the electron completely to form Cl -. HCl The Chlorine wants the electrons more than the Hydrogen. Thus we have +δ HCl -δ. Cl 2 (ClCl) The Chlorine molecules want the electrons equally so they form a non-polar molecule with NO partial or full charges. 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... :O:H H.. O::C::O
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 _________ + Non-Metal _________ideSodium Chlorine Sodium Chloride NaCl Metals (Transition Metals) and Non-Metals Metal ______ +Roman Numeral (__) + Non-Metal ________ide Iron III Bromine Iron ( III ) Bromide FeBr 3 Compare with Iron ( II ) Bromide FeBr 2
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) _______ + ous or ic + Non-Metal ________ide Ferrous 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 N 2 O 5 Dinitrogen pentoxide CS 2 Carbon disulfide
Lets Practice! Name the following. CaF 2 K2SK2S CoI 2 SnF 2 SnF 4 OF 2 CuI 2 CuI SO 2 SrS LiBr Strontium Sulfide Lithium Bromide Copper ( I ) Iodide or Cuprous Iodide Sulfur dioxide Copper ( II ) Iodide or Cupric Iodide Oxygen diflouride Tin ( IV ) Flouride or Stannic Flouride Tin ( II ) Flouride or Stannous Flouride Cobalt ( II ) Iodide or Cobaltous Iodide Potassium Sulfide Calcium Flouride
Polyatomic Ions (partial list from page 195 (193 2 nd edition)) Ammonium……………... Ammonium……………... Nitrate…………………… Nitrate…………………… Permanganate………….. Permanganate………….. Chlorate………………… Chlorate………………… Hydroxide………………. Hydroxide………………. Cyanide…………………. Cyanide…………………. Sulfate…………………... Sulfate…………………... Carbonate………………. Carbonate………………. Chromate……………….. Chromate……………….. Acetate………………….. Acetate………………….. Phosphate………………. Phosphate………………. NH 4 + NH 4 + NO 3 - NO 3 - MnO 4 - MnO 4 - ClO 3 - ClO 3 - OH - OH - CN - CN - SO SO CO 3 2- CO 3 2- CrO 4 2- CrO 4 2- C 2 H 3 O 2 - C 2 H 3 O 2 - PO 4 3- PO 4 3-
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
Lets Practice! HF Na 2 CO 3 H 2 CO 3 KMnO 4 HClO 4 H2SH2S NaOH CuSO 4 PbCrO 4 H2OH2O NH 3 Hydrooxic acid (no……just water) Nitrogen trihydride (no..just ammonia) Copper ( II ) sulfate or Cupric sulfate Lead ( II ) chromate or Plubous chromate Sodium hydroxide Hyrdogen sulfuric acid Perchloric acid Potassium permanganate Sodium carbonate Hydroflouric acid Carbonic acid