Unit Three: Molecules & Compounds 0 Unit Three: Molecules and Compounds Table of Contents: Pg. 1 Table of Contents Pg. 2-3 Bonding (Intramolecular Forces) Covalent and Ionic Bonding Assignment on Pg. 36 Pg. 4-5 Lab Two: Investigation into Polymers Pg. 6-9 Ionic Compounds Determining Number of Atoms & Criss Cross Method Assign on Pg. 37 Ionic Bonding Lewis Dot Assign Pg. 38 Determining Charges Assign Pg. 39 Pg. 10-11 Covalent Compounds Covalent Bonding Lewis Dot Assign Pg. 40 Pg. 12-16 VSEPR VSEPR Assign Pg. 41 Pg. 16-18 Intermolecular Forces Ionic, Polar Covalent or Non-polar Covalent Assign Pg. 42 Intermolecular Forces Assign Pg. 43 Pg. 19-20 Nomenclature for Ionic Compounds Naming Ionic Compounds Assign Pg. 44 Pg. 21-26 Lab Three: Formula Writing and Chemical Names Pg. 27 Nomenclature for Covalent Compounds Naming Covalent Compounds Assign Pg. 45 Writing Formulas From Names Assign Pg. 46 Pg. 27-28 Nomenclature for Acids Naming Acids Assign Pg. 47 Pg. 29-32 Nomenclature for Organic Compounds Naming Organic Compounds Assign Pg. 48 Structure of Organic Compounds Assign Pg. 49 Pg. 33-34 Solids (Independent Study) Types of Solids Assign Pg. 50 1 Bonding Recall: Recall the structure of the atom: o An atom is composed of 3 different particles: __________________________, __________________________, __________________________. The main particle involved in bonding is the __________________________. Recall the octet rule: Remember all atoms like to have _______ valence electrons in order to be stable. Collision Theory: Bonding between atoms requires things: o Energy: __________________________ energy is required for bonding to occur. This kinetic energy is usually obtained through __________________________ (ie. the atoms or molecules bump into one another). o __________________________: The way the atoms are placed during the collision matters. Not one orientation works for __________________________ atoms/molecules (ie. The atoms or molecules need to bump into one another in the right spot). Bonding: Bonding is when 2 or more atoms share or transfer __________________________ to try to fill or empty their valence shells. An atom with 6 valence electrons would want to gain or share _________ electrons in order to fill its valence shell. Intramolecular Forces: “Intra” is Latin for “__________________________”. Intramolecular forces are forces within a molecule or compound holding it ______________________. There are 2 types of intramolecular forces: ionic bonding and __________________________ bonding. 2 Ionic Bonding: o Occurs between a __________________________ and a __________________________. o Occurs when electrons are __________________________ from one atom to another (from metal to the non-metal). o Ionic bonding creates ions The metal __________________________ an electron/ electrons and becomes a __________________________ (so it is positive). The non-metal __________________________ an electron/ electrons and becomes an __________________________ (so it’s negative). o _________________________________ are formed when ionic bonding occurs. Covalent Bonding: o Occurs between 2 __________________________. o Occurs when electrons are __________________________ between atoms. o __________________________ form when covalent bonding occurs. o Covalent bonds can occur as single, double, triple or quadruple bonds. Single bonds occur when _______ electron pair is shared between 2 atoms Double bonds occur when ______ electron pairs are shared between two atoms. It is __________________________ than a single bond (but not 2 times stronger) Triple bonds occur when __________________________ electron pairs are shared between 2 atoms. Triple bonds are very __________________________ bonds. One of the strongest bonds known is the triple bond between __________________________. This is why many explosives contain nitrogen. Because when those compounds break apart and nitrogen gas is formed (N2), a large amount of energy is released. Quadruple bond are __________________________ and do not occur naturally. They can only be observed under high vacuum conditions and are extremely unstable. This would occur when _______ electron pairs are shared between 2 atoms. Examples: To determine whether a compound is ionic or covalent we look at the atoms that make up the compound. Remember that every element symbol starts with a __________________________ letter, so to determine how many different elements there are in a compound, you just look at the number of capital letters. To determine whether the compound is ionic or covalent, look at whether the elements are __________________________ or __________________________: NH3 NiBr3 MgCl2 Al(OH)3 H2S (see Covalent Bonding and Ionic Bonding Assign Pg. 36) 3 Lab Three Investigation into Polymers Background information: Polymers are long chains of atoms bonded together covalently. These long chains are made up of repeating structural units (same order of atoms over and over). Since polymers are long chains, they can get twisted and tangled together. If a substance can be twisted, pulled, or compressed and it resumes back to its original form, it is usually a type of polymer called an elastomer. Elastomers have elastic properties. That is they can by pushed or pulled and they still go back to their original form. An example of an elastomer is a rubber band or a car tire. The covalent bonds along the chain are strong, but the bonds between chains are normally weak. However, additives such as borax allow the formation of strong "cross-links" between chains. As the number of cross-links increases, the material becomes more rigid and strong. The liquid latex, or glue, which we will use in this experiment, contains small globules of hydrocarbons (hydrogen and carbons bonded together) suspended in water. These globules are polymers and are called polyvinyl acetate. The polymer putty is formed by joining the globules using a cross linker sodium tetraborate (found in borax). Sodium borate acts as a cross-linker to the original hydrocarbon polymers. The cross-linker can be thought of as rungs joining two sides of a ladder. The putty is held together by very weak intermolecular bonds that provide flexibility around the bond and rotation about the chain of the cross-linked polymer. 4 Purpose: The objective of this experiment is to cross-link a polymer and observe the changes in the physical properties as a result of this cross-linking. Materials: Plastic bag Water White liquid glue Food colouring. Borax General Safety Guidelines: Since borax solid (a bleaching agent) and solution will burn the eyes, goggles should be worn. Hands should always be washed after kneading the polymers and finishing the experiment. Procedure: 1. Obtain a plastic bag. 2. Obtain your sample of white glue in the plastic bag. Be sure to make your observations. 3. Place one drop of food colouring in the plastic bag. Close the back and mix (Observations)- Do not use more than 2 drops of food colouring or that will ruin your experiment. 4. Obtain 4-5mL of 4% Borax solution. Slowly add this to your glue mixture while continually stirring. (Observations, Observations, Observations!) 5. Make observations about what you have created. The Polymer is safe to touch, but not to eat or taste because it is toxic if ingested. Get creative with your observations (Dropping it, stretching slowly/quickly, compare your polymers with others in the class, etc.) 6. Place your polymer in the plastic zipper seal bag and seal it with the least amount of air possible. 7. Clean up. Your polymer should go in the plastic bag and the bag should be sealed whenever you are not observing. 8. Take your polymer home and place it in the fridge for about 15 minutes. Make observations about your polymer when the temperature is decreased. Analysis Questions: 1. What would be the effect (your thoughts) of adding more sodium borate solution? 2. Where does all of the water go? Remember that you stated with a solution made up of 96% water. 3. How do the physical properties of the glue change as a result of adding the sodium borate? 4. Why does a car tire appear to be flat in the summer even though the gas inside is hotter than in the winter. 5 Ionic Compounds Chemical Formula How to determine the charge of an ion: If an atom gains electrons it will become __________________________ charged (an anion) because it is gaining negative charges. If an atom loses electrons it is losing negative charges so it will be __________________________ (a cation). For each of the atoms listed below, determine how many valence electrons they have, how many valence electrons they would need to gain or lose to fill their valence shell, and what the charge would be on the ion with a full valence shell. Element # of Valence Electrons # of e- to gain or lose Charge Sulfur Hydrogen Calcium Carbon How to Determine Chemical Formula for Ionic Compounds: In order to determine the chemical formula for a compound we need to look at the __________________________ that the atoms would have with a __________________________ valence shell. For the transition metals we will always be given its charge. # of Atoms: First we need to be able to read how many atoms are in a molecule: o O= o O2= o Na2O= o 3Na2O= o Mg(OH)2= o (NH4)2SO4= 6 Chemical Formula for Binary Compounds: To figure out how many of each atom goes into a molecule we use the __________________________ method: Sr and Cl Look on the common ion sheet to find the charges: Drop the Charge (leave the number): Criss Cross the numbers: Ones do not need to be written: Ba and O Cu and F Chemical Formula for Ionic Compounds that Contain Polyatomic Ions For polyatomic ions, we look on the common ion sheet to find their charge. We use this charge in our criss cross method. Ammonium NH4+1 and Ferrocyanide Fe(CN)6 4Polyatomic ions need to have __________________________ around them (if there is more than one) Magnesium and Carbonate Cobalt (III) and Sulfate (See Determining Number of Atoms and Criss Cross Assign Pg. 37) 7 Lewis Dot (Ionic) How to determine the Lewis dot structure for ionic compounds Example: Determine the Lewis dot structure for the ionic compound that will form between calcium and chlorine. 1. Determine the number of atoms of each element there will be (Criss Cross). 2. Draw out the Lewis dot structure for each of the atoms. Circle the electrons that are going to leave and create the cation and draw arrows to the anion they are going to. 3. Draw out the Lewis dot for each of the ions created and put them in brackets with the charge in the upper right corner outside of the brackets. Examples: Aluminum and Oxygen (See Ionic Bonding Lewis Dot Assign Pg. 38) 8 Determining the Charge (Transition metals) Determining charge when given the chemical formula: Work backwards: What is the charge on iron? FeCl3 o We know chlorine has a charge of ______ and there are ______ chlorine ions, so copper must have a charge of ______ in order for the compound to have a neutral charge. What is the charge on copper? Cu(NO3)2 o We know NO3 has a charge of ______ (from our common ion sheet), so copper must have a charge of ______. This is written as copper (II). What is the charge on Iron in Fe2O3? o Oxygen has a charge of ______ normally. There are ______ oxygens so the oxygens have a total charge of ______ in total. This means that the irons must have a total charge or ______. There are 2 iron atoms and the molecule is neutral so they must each have a charge of ______ in order to equal ______. What is the charge on iron in FeCO3? o First we need to find the polyatomic ion (it won’t always be in brackets). A compound contains a polyatomic ion if it is ionic and there are more than ______ elements. The polyatomic ion will be the first few elements if it is a _______________________ and the last few elements if it is an _______________________. Most polyatomic ions are anions, so usually the polyatomic ion will be at the _______________________. o Carbonate has a charge of ______ so iron has a charge of ______. Example: PbCl2 As(OH)5 FePO4 (See Determining Charges Assign Pg. 39) 9 Covalent Molecules Number of Bonds How to determine the number of covalent bonds that form: Determining the number of covalent bonds that form is similar to determining charge. We look at how many _______________________ an atom needs to fills its octet (this is the number of bonds that will form). When atoms bond covalently they _______________________ their valence electrons. Carbon has _____ valence electrons. It needs _____ electrons to fill its valence shell. This means it will form _____ bonds (if they are single, or it could form 2 double bonds, or 1 triple bond and one single bond). Oxygen has 6 valence electrons and needs _____ to fill its valence shell. This means it will form _____ bonds (if they are single, or 1 double bond). Nitrogen has _____ valence electrons and needs _____ electrons to fill its valence shell. This means it will form _____ bonds (if they are single). Lewis Dot (Covalent) Draw Lewis dot structure for molecules (covalent): Fluorine bonding with itself (F2): 1. Determine how many atoms of each element there will be (if it’s not given). 2. Draw the Lewis dot for each atom. (In the space below) 3. Look at the lone electrons. These are the electrons involved in bonding. Circle one lone electron from one atom and one lone electron from another. This will form a bond. If there are three or more atoms, make sure every atom is involved in the bonding. 4. Redraw the molecule so that the atoms are beside one another and the shared electrons are between them. 5. If asked to draw a structural diagram, draw lines to replace bonded pairs of electrons. 10 Examples: Oxygen bonding with itself: Chlorine bonding with hydrogen: CF4: Nitrogen bonding with itself: (See Covalent Bonding Lewis Dot Assign Pg. 40) 11 VSEPR What do the molecules really look like? Next we will look at what a molecule looks like in 3 dimensional space. We use molecular ______________________ and VSEPR Theory. VSEPR stands for __________________________________________ __________________________________________. The VSEPR theory determines the ______________________ of a molecule by looking at the electrons surrounding the central atom and whether they are shared pairs of lone pairs (bonding or non-bonding pairs). Determine Molecular geometry using VSEPR: 1. Determine the Lewis dot formula 2. Determine the total number of electron pairs around the central atom 3. Use the table provided to determine the electron pair geometry 4. Use the table provided to determine the shape 5. Use the diagram chart to draw a 3D diagram VSEPR Chart Total pairs of e- around central atom Number of bonded pairs Electron Pair geometry Molecular geometry 2 2 Linear Linear 3 2 Trigonal Planar Bent 3 3 Trigonal Planar Trigonal Planar 4 2 Tetrahedral Bent 4 3 Tetrahedral Trigonal Pyramidal 4 4 Tetrahedral Tetrahedral 5 2 Trigonal Bipyramidal Linear 5 3 Trigonal Bipyramidal T-Shaped 5 4 Trigonal Bipyramidal Seesaw 5 5 Trigonal Bipyramidal Trigonal Bipyramidal 6 2 Octahedral Linear 6 3 Octahedral T-Shaped 6 4 Octahedral Square Planar 6 5 Octahedral Square Pyramidal 6 6 Octahedral Octahedral 12 VSEPR Geometry 3D diagrams: E = Central Atom X =Bonded Atom = Unbonded pair of electrons 13 Examples: OF2 Oxygen has 4 pairs of electrons around it, _____ are bonded _____ are lone, so it has a geometry of ______________________ ______________________. The 3D drawing for tetrahedral bent is: So you just need to fill in the atoms where they belong: PCl3 PCl3 has _____ pairs of electrons around it, _____ of the pairs are bonded. This means that PCl3 has a geometry of ______________________, ______________________ ______________________. 14 Sometimes in a double or triple bond you have to assume that the atom has only _________ shared pair of electrons in order to get the proper geometry. CS2 Even though this actually has ______ shared pairs of electrons and all are bonding electrons, the shape is linear. In this molecule we assume that Carbon has ______ pairs of electrons and both are bonded. Normally assume that atoms want to have _____ valence electrons, however sometimes atoms like to have more. In situations like this we say that the atom ______________________ the octet rule. In this class you will always be told if an element breaks the octet rule. XeF4 Xe has _____ valence electron and Fluorine has _____, This molecule has ______ pairs of electrons around it, and 4 of them are involved in bonds so its geometry is ______________________, ______________________ ______________________. 3D drawing: (See VSEPR Assign Pg. 41) 15 Balloon Molecules Assignment Read through the whole activity before you begin, as there is some after class participation that is required. Create the molecules assigned to your group using the balloons provided. There are 2 different coloured balloons. Assign one colour to represent the bonded electron pairs and the other to represent the lone electron pairs. Make sure you specify which is which. Create your molecules so that it is stable enough to get knocked over and still maintain its shape. You will be provided with tape and balloons. After you have created your molecule with the balloons, label it with masking tape and your names. You then need to make a 3 dimensional drawing of each of your molecules using the actual atoms (not drawings of the balloons). Use the dashed and solid lines to represent the atoms that go into the page and the atoms that come out of the page. Each member of your group should submit a drawing of both molecules. On this paper you need to write down which balloon colors represent bonded electrons and which represent lone pairs. Don`t forget your names! When you have finished building and drawing your molecules, you need to find a space on the counter and place all of your molecule representations together. You can then work on the “VSEPR” assignment. After today`s class, I would like you to go to the virtual classroom and post a comment saying which molecule your group had and what you think the geometry of that molecule is. Since each group has 2 molecules, each person should post a different molecule. For the group of 3, 2 of you will have to post the same molecule. Intermolecular Forces Inter is Latin for “______________________” Occurs when bonds or forces occur between ______________________ (covalent). Intermolecular forces hold a molecule in a certain spot. The three types of intermolecular forces we will look at are polar bonds, hydrogen bonds and van der waals forces. Polarity Non-polar molecules have ______________________, or approximately equal pull on the electrons. This occurs when the atoms in the molecule are the ______________________ or have a similar ______________________________. Electronegativity generally increases as you move from left to right in a period and decreases as you move from the top to the bottom of a family. Polar molecules have a ______________________ positive or ______________________ negative charge due to one atom having a stronger ______________________ on the electrons. This occurs when there is a large ______________________ in electronegativity so one atom pulls stronger on the ______________________ than the other atom. The more electronegative atom will have a partial 16 negative charge because it has a ______________________ pull on the electrons, and the less electronegative atom will have a partial positive charge because the electrons are being pulled ______________________. o Example, Chlorine has an electronegativity of _________ and hydrogen has an electronegativity of _________. Since chlorine has a stronger pull on the electrons they will be ______________________ to the chlorine atom and the chlorine atom will have a slightly ______________________ charge. This means the hydrogen will have a ______________________ positive charge. o To show the direction of polarity we draw a dipole. A dipole is drawn to show where the electrons in the molecule are more likely to be found. It is drawn like this: o Another way to show the slight negative charge is to use the symbol that stands for slightly. The difference in the electronegativity can tell us what type of bond is formed. o If the difference is 0-0.4 then the bond is ______________________ covalent o If the difference is 0.4- 1.7 then the bond is ______________________ covalent o If the difference in electronegativity is greater than 1.7, then the bond is ______________________. If the difference in electronegativity is very very large then it is usually an ionic bond because one atom pulls so hard on the electrons that it pulls them completely away from the other atom. Remember that there is no distinct line of separation so the rules above are more like guidelines. Remember an ionic bond will occur between a metal and a non-metal and covalent is between 2 non metals. Example: HI (See Polar vs. Non-Polar Assign Pg. 42) 17 Hydrogen bonds: Hydrogen bonds are weak bonds formed by the attractions of slightly negative atoms to the slightly positive ______________________ when bonded covalently. Hydrogen bonds occur between hydrogen, and ______________________, ______________________ or ______________________. Hydrogen bonds are also called ______________________. Hydrogen bonds are weaker than covalent bonds but ______________________ than van der waals. Example: H2O Van der Waals: Van der Waals forces are a type of intermolecular force that deals with the ______________________ of molecules. The Van der Waals forces are those where a slightly negative atom from one molecule is attracted to a slightly positive atom from another molecule. Van der Waals forces are weaker than both the covalent bond and the hydrogen bond (Technically H-Bonds and London Dispersions forces are both types of Van Der Waals Forces) Example: CO2 London Dispersion Force: The ______________________ intermolecular force Electrons in a molecule are constantly ______________________. In a non-polar molecule, on average the electrons are distributed equally over the molecule, but occasionally one side or the other will gain a small excess of electron density. When this occurs, the molecule has a temporary ______________________- one side of the molecule has a slight + charge, the other a slight - charge. All molecules have dispersion forces. Example: Cl2 (see Intermolecular Forces Assign Pg. 43) 18 Nomenclature for Inorganic Compounds IUPAC Naming System (Nomenclature) IUPAC = ________________________________________________________________________________________ Naming Ionic Compounds: When naming ionic inorganic compounds we always write the ______________________ first (or the cation) and then the ______________________ (or the anion). For compounds that do not contain ______________________ ions: We first write the metal, then the non metal with “ide” added on. Ex. Li2S= AlCl3= MgO= For compounds that do contain polyatomic ions: We write the metal then the polyatomic ion (do not add the “ide” ending) Ex. K3PO4= (NH4)2CO3= Na2SiO3= MgSO4 = Transition Metals When the metal involved in the ionic bond has more than one oxidations state/possible ______________________ we need to identify which ion it is. This usually occurs with the ______________________ metals. Any ion that appears on your common ion sheet more than once is one of these types of metals. There are 2 ways to do this. The first way (the way that is the newer and preferred method) is to use __________________________ to identify which ion it is. o Ex. Fe(CN)3= First we need to find what ______________________ iron has (Since cyanide has 1 charge and there are 3 of them, iron must have a _____ charge). We would then use the roman numeral ______ to identify this ion. o The rules are the same as above but now we add the roman numeral in the ______________. o The compound Fe(CN)3 would be named: 19 The second way to identify the ion is to use the -ous or -ic endings. o The ion with the lower oxidation state (or lower numerical charge ignoring the + or -) gets the ________ending, and the ion with the higher oxidation state gets the ______ ending. o So in the example above, Iron 3+ is the iron ion with the higher oxidation state (the other ion is iron (II) ) so it would get the ________ ending. Notice that on your table of common ions, Iron (III) also has the name ______________________. So… Fe(CN)3 would be named: (See Naming Ionic Compounds Assign Pg. 44) Writing Compounds from the names: Just work backwards (and Use Criss Cross): Ex. Magnesium Chlorite Ex. Lead (II) Iodide 20 Name: Lab Partner: Lab Four Teacher: Date: Formula Writing and Chemical Names Introduction: A chemical formula is a combination symbols and numerical subscripts that represent the composition of a compound. The symbols indicate which elements are present and the numerical subscripts indicate the relative proportion of each element in the compound. These proportions can be predicted using the oxidation numbers (charges) of the elements. When atoms acquire a charge they are called ions. It is important that all scientists use the same system for writing chemical formulas. This helps to ensure clear and consistent transmission of information. Therefore, the following rules should be used for writing chemical formulas: 1. In a neutral compounds the sum of the charges of the elements (ions) must equal zero. One positive(+) charge will neutralize one negative(-) charge. 2. Elements (ions) with a positive charges are written first 3. When the relative proportion of the polyatomic ion in a compound is greater than one, the symbol for that ion must be enclosed in parenthesis and followed by a numerical subscript indicating its relative proportion, as in the ternary compound Aluminum Sulfate whose formula would be Al2(SO4)3. Purpose: Students will observe precipitate formation and write chemical formulas and chemical names for the precipitate. Equipment: Materials: Pipettes Solutions of Glass Plate NO3-, CO32-, PO43-, Zn2+, SO42-, Cu2+, Mg2+, K Procedure: 1. Read through the entire lab procedure, put on your safety glasses. 2. Insert the work page under your glass plate and place on top of work table 3. Make you hypothesis before each reaction occurs. 4. Make your observations of each solution before any reaction occurs. 5. Combine two drops of cation solution with two drops of anion solution in the appropriate grid square. Be careful not to let the dropper touch the drops of the other solutions. 21 6. Observe the reaction (if any) and record you observations on the corresponding square of the data table. Also record your more detailed observations in the spaces below. 7. Repeat steps above until you have combined all sixteen possible reactions. 8. Make observations of reaction’s using the corresponding number (in the chart). Data Analysis: Observations Before: NO3-: CO32-: PO43-: SO42-: Zn2+: Cu2+: Mg2+: K+: 22 Hypothesis: NO3- CO32- PO43- SO42- Zn2+ 1 2 3 4 Cu2+ 5 6 7 8 Mg2+ 9 10 11 12 K+ 13 14 15 16 Data: Descriptive observations 1. 2. 3. 4. 23 5. 6. 7. 8. 9. 10. 11. 24 12. 13. 14. 15. 16. Analysis: 1. What is a chemical formula? 2. What information does a subscript in a chemical formula provide? 3. What is a formula unit? 4. When do you need to use a parenthesis in writing a chemical formula? 5. When do you need to use a roman numeral in the name of a compound? 6. Write out the chemical formula and chemical name for each solution that underwent a chemical change. Conclusion: State which ions experience chemical reactions when combined. 25 Naming Covalent Compounds: Binary compounds: These are compounds that contain only _____ elements. When naming binary compounds we use ______________________ to indicate the amount of each element present. 1 2 3 4 5 6 7 8 9 10 mono di tri tetra penta hexa hepta octa nona deca We rarely use mono, because normally we just assume that there is one if no prefix is present. Mono is only used for ______________________. Ex. CO2 P4O10 SO3 N2O4 (See Naming Covalent Compounds Assign Pg. 45) Write Chemical Formula from Name: Just write what the formula says: Dinitrogen trioxide Diphosphorus pentoxide (See Writing Formulas From Names Assign Pg. 46) Naming Acids: Naming acids that are binary: These would be covalent molecules that contain a ______________________ and another molecule (Usually a halogen or sulfur or phosphorus) H__ Hydro______ic Acid o Ex. HI Hydroiodic acid o Ex. Hydrochloric acid: HCl 26 Naming Acids that are polyatomic: These are covalent molecules containing ______________________ and a polyatomic ion. First we need to point out a pattern that you may or may not have already recognized: o There are many sets of polyatomic ions that are similar to each other where the only difference is the number of oxygen atoms. The ions with more oxygens get an “______________________” ending and the ion with less oxygens gets an “______________________” ending. Ex. Phosphate ______________________and Phosphite ______________________ Nitrate: ______________________ Nitrite: ______________________ The Oxygen containing polyatomic ions are named as follows: Least Oxygens: hypo_____ite ______ite ______ate Most Oxygens: per_______ate o These are the polyatomic ions that are involved in acids When naming acids containing polyatomic ions we name them first by writing the name of the ion. o We change the ending. If the ion ends in -ate we put an ______________________on it. If the ion ends in ite we put an ______________________ending on it. o Ex. H3PO3 ______________________ is the polyatomic ion in this acid, so the name is ______________________. o Ex. HClO3: ClO3 is ______________________. Since it has an ate ending we name it ______________________. o Ex. Iodic acid. This has an ic ending so the ion must have an ______________________ending. Iodate (IO3-). Then we add however many ______________________we need to make the molecule neutral. So this molecule needs ______________________ hydrogen ______________________ (We write the hydrogen first, then the polyatomic ion) o Ex. Chlorous acid. This has an ous ending so we are looking for an ion with an _________ (with chlorine and oxygen). Chlorite (ClO2-). We add however many hydrogens we need. HClO2 Note: On exams and assignments where naming is required, it is important that you are able to identify acids and name them appropriately. For example you name Hydrochloric acid hydrochloric acid, not hydrogen chloride. (See Naming Acids Assign Pg. 47) 27 Nomenclature for Organic Compounds Types of Hydrocarbons: IUPAC Naming System Organic compounds are those which contain ______________________ (excluding oxides and carbonates). Things to know for naming: Alkanes are organic compounds that contain only ______________________ bonds, Alkenes are carbon compounds that contain one or more ______________________bonds Alkynes are organic compounds that contain one of more ______________________ bonds. All Alkanes follow the ______________________rule. All Alkenes containing one double bond between carbons follow the ______________________ rule. These rules will help you to determine whether a molecule is an alkane, or an alkene. Ex. CH4 is an Alkane because if n=1, then the molecule would be C1H2(1)+2, Which is CH4. Is C2H6 and alkane or alkene? Is C2H2 an alkane or an alkene? Is C3H6 an alkane or alkene? Naming Prefixes When naming organic compounds we must first find the longest chain of carbons in the molecule. Each number of carbons in the chains corresponds to a different prefix. Number of Carbons Prefix Number of Carbons 1 6 2 7 3 8 4 9 5 10 Prefix 28 Suffix If the molecule contains all single bonds the suffix is “_______________”. If the molecule contains a double bond the suffix is “______________”. If the molecule contains a triple bond the suffix is “_______________”. Ex 1 Alkenes and alkynes are named using a ______________________ to indicate where the double or triple bond is located. Always number the carbons so that you get the ______________________possible number. Examples: Ex. 2 Ex. 3 Ex 4. Ex. 4 If the Compound contains 2 or more double bonds you would need to use di, tri etc. Ex. 1,2 butadiene or buta-1,2-diene Alkyl groups If you remove a hydrogen atom from one of these carbon chains and add a branch, you get an alkyl group. These are also named based on the number of carbons but the suffix is “_______” For example methyl –CH3. These alkyl groups can then bond with another compound in place of a hydrogen. 29 To name these we first identify the ______________________ carbon chain. Next number the carbons. To write the name we first write the number, then the name of the alkyl group, then the name of the longest carbon chain. # - alkyl group longest carbon chain Ex 5. When naming compounds with more than one alkyl group, you must name them ______________________. You also number the carbons so that the ______________________ group in the name has the lowest number. If you have two of the same alkyl group you name them as follows: #, # - dialkyl group longest carbon chain If you had three of the same alkyl groups you would use 3 numbers to indicate where they are located and the prefix tri on the name of the alkyl group. Ex 6. Ex 7. Ex 8. 2-methylpropane Ex 9. 3, 3- diethyl hexane 30 Line Forms: = = = Draw the molecules from examples 1-9 in line form (See Organic Compounds Assign Pg.48 &49) 31 Solids- Independent Study http://www.chm.davidson.edu/vce/crystals/networksolids.html Crystalline Solids Crystalline solids fall into one of four categories. Type of Solid Interaction Properties Examples Ionic Ionic High Melting Point, Brittle, Hard, Often dissolve in water. NaCl, MgO Molecular Hydrogen Bonding, Dipole-Dipole, London dispersion Low Melting Point, Nonconducting, can be crystal H2, CO2 Metallic Metallic Bonding Variable Hardness and Melting Point (depending upon strength of metallic bonding), Conducting, usually not crystals Fe, Mg Covalent Bonding High Melting Point, Hard, Nonconducting, tend not to dissolve in water. Some forms of C, SiO2 Network All four categories involve packing discrete molecules or atoms into a lattice or repeating array, though network solids are a special case. The categories are distinguished by the nature of the interactions holding the discrete molecules or atoms together. In ionic and molecular solids, there are no chemical bonds between the molecules, atoms, or ions. The solid consists of discrete chemical species held together by intermolecular forces that are electrostatic or coulombic in nature. This behaviour is most obvious for an ionic solid such as NaCl, where the positively charged Na+ ions are attracted to the negatively charged Cl- ions. Even in the absence of ions, however, electrostatic forces are operational. For polar molecules such as CH2Cl2, the positively charged region of one molecular is attracted to the negatively charged region of another molecule (dipole-dipole interactions). For a nonpolar molecule such as CO2, which has no permanent dipole moment, the random motion of electrons gives rise to temporary polarity (a temporary dipole moment). Electrostatic attractions between two temporarily polarized molecules are called London Dispersion Forces. Hydrogen bonding is a term describing an attractive interaction between a hydrogen atom from a molecule or a molecular fragment X–H in which X is more electronegative than H, and an atom or a group of atoms in the same or a different molecule, in which there is evidence of bond formation. Dots are employed to indicate the presence of a hydrogen bond: X–H···Y. The attractive interaction in a 32 hydrogen bond typically has a strong electrostatic contribution, but dispersion forces and weak covalent bonding are also present. In metallic solids and network solids, however, chemical bonds hold the individual chemical subunits together. The crystal is essential a single, macroscopic molecule with continuous chemical bonding throughout the entire structure. In metallic solids, the valence electrons are no longer exclusively associated with a single atom. Instead these electrons exist in molecular orbitals that are delocalized over many atoms, producing an electronic band structure. The metallic crystal essentially consists of a set of metal cations in a sea of electrons. This type of chemical bonding is called metallic bonding. In network solids, conventional chemical bonds hold the chemical subunits together. The bonding between chemical subunits, however, is identical to that within the subunits, resulting in a continuous network of chemical bonds. Two common examples of network solids are diamond (a form of pure carbon) and quartz (silicon dioxide). In quartz one cannot detect discrete SiO 2 molecules. Instead the solid is an extended three-dimensional network of ...-Si-O-Si-O-... bonding. (See Types of Solids Assign Pg. 50) 33 Name:__________________________________________ Covalent and Ionic Bonding Assignment Classify the following compounds as ionic (metal + non-metal), covalent (non-metal + non-metal) or both (compound containing a polyatomic ion). 1. CaCl2 _________________________________ 2. CO2 _________________________________ 3. H2O _________________________________ 4. BaSO4 _________________________________ 5. K2O _________________________________ 6. NaF _________________________________ 7. Na2CO3_________________________________ 8. CH4 _________________________________ 9. SO3 _________________________________ 10. LiBr _________________________________ 11. MgO _________________________________ 12. NH4Cl _________________________________ 13. HCl _________________________________ 14. KI _________________________________ 15. NaOH _________________________________ 16. NO2 _________________________________ 17. AlPO4 _________________________________ 18. FeCl3 _________________________________ 19. P2O5 _________________________________ 20. N2O3 _________________________________ 34 Name: _______________________________________ Determining Number of Atoms Determine the number of atoms in each of the following compounds: 1. KCl: ___________ 8. MgCl2: ___________ 15. Hg2Cl2: ___________ 2. NaCl: ___________ 9. CH3COOH: ___________ 16. (NH4)3PO4: ___________ 3. CaCl2: ___________ 10. CuC2H3O2: ___________ 17. Mg(C2H3O2)2: ___________ 4. KNO3: ___________ 11. Ba(OH)2: ___________ 18. Mg(NO2)2: ___________ 5. H2SO4: ___________ 12. NH4Br: ___________ 19. As2(SO4)5: ___________ 6. CaCO3: ___________ 13. Ca3(PO4)2: ___________ 20. Zn3(PO4)2: ___________ 7. C2H6: ___________ 14. Al(OH)3: ___________ Criss Cross Method Determine the chemical formula for the compounds created by the combination of the ions below. Cl- O2- SO32- PO43- NO2- OH- CH3COO- Na+ Mg2+ Co3+ NH4+ Fe3+ As5+ H+ 35 Name:_____________________________ Ionic Bonding Lewis Dot Assignment Draw the Lewis dot structure for the ionic compounds created from the elements below. Be sure to draw the Lewis dot in 2 steps, to show how the electrons are involved in bonding. 1. K + F 2. Mg + I 3. Be + S 4. Na + O 5. Al + Br 36 Name:_________________________________ Determining Charges Assignment: 1. What is the charge of copper in the following molecule? CuBr2 2. What is the charge of iron in the following molecule? FeBrO3 3. What is the charge of cobalt in the following molecule? CoCrO4 4. What is the charge of copper in the following molecule? Cu3(PO4)2 5. What is the charge of nickel in the following molecule? Ni3(PO4)2 6. What is the charge of Silver in the following molecule? Ag2HPO4 7. What is the charge of Manganese in the following molecule? MnSO4 8. What is the charge of lead in the following molecule? Pb(CrO4)2 9. What is the charge of chromium in the following molecule? Cr2(C2O4)3 10. What is the charge of Arsenic in the following molecule? As3(BO3)5 37 Name:_____________________________________ Covalent Bonding Lewis Dot Assignment Draw the lewis dot structure for the covalent molecules created from the elements below. Be sure to draw the lewis dot in 2 steps, to show how the electrons are involved in bonding. 1. H + H (H2) 2. F + F (F2) 3. O + O (O2) 4. N + N (N2) 5. C + O (CO2) 6. H + O (H2O) 38 Name: ____________________________ VSEPR Assign Determine the electron pair geometry and the molecular geometry for the following, then draw the 3D structure of the molecule: Follow Octet: Break the Octet: CH4 XeH2 ArCl4 NF3 NH5 FCl3 SBr2 OBr4 39 Name:______________________________ Ionic, Polar Covalent or Non-polar Covalent Assignment Determine whether the following bonds are ionic, non-polar covalent or polar covalent. 1. N2: The Nitrogen Nitrogen bond 2. HF: The hydrogen fluorine bond 3. LiBr: The lithium Bromine bond 4. AuCl3: The gold Chlorine bond 5. H2O: The hydrogen oxygen bond 6. CH3OH: The carbon hydrogen bond 7. CH3OH: The Carbon Oxygen bond 8. SO3: The Sulphur Oxygen bond 9. KI: The Potassium Iodine bond 10. Fe2O3: The iron, Oxygen bond. 40 Name:___________________________________ Intermolecular Forces Assignment Determine whether the following molecules will have polar bonds, H-bonds, Van der waals forces or London Dispersion forces. Be sure to include all forces (i.e. there may be more than one that applies) 1. NH3 2. I2 3. CH4 4. HF 5. O2 6. HBr 7. Br2 8. BF3 41 Name:________________________________ Naming Ionic Compounds Assignment Name the following ionic compounds using Roman Numerals where necessary: 1. BaCl2 ___________________________________ 2. Ag2O ___________________________________ 3. CuBr ___________________________________ 4. FeO ___________________________________ 5. MgS ___________________________________ 6. Al2O3 ___________________________________ 7. K2S ___________________________________ 8. CrCl2 ___________________________________ 9. Ba3P2 ___________________________________ 10. BeS ___________________________________ 11. MnO ___________________________________ 12. FeSO4 ___________________________________ 13. FeCl3 ___________________________________ 14. Zn3(PO4)2 ___________________________________ 15. NH4NO3 ___________________________________ 16. Al(OH)3 ___________________________________ 17. CuC2H3O2 ___________________________________ 18. PbSO3 ___________________________________ 19. NaClO3 ___________________________________ 20. CaC2O4 ___________________________________ 21. Fe2O3 ___________________________________ 22. NaHSO4 ___________________________________ 23. Hg2Cl2 ___________________________________ 24. Mg(NO2)2 ___________________________________ 25. CuSO4 ___________________________________ 26. NaHCO3 ___________________________________ 27. NiBr3 ___________________________________ 28. Be(NO3)2 ___________________________________ 29. AuCl3 ___________________________________ 30. KMnO4 ___________________________________ 42 Name:______________________________ Naming Covalent Compounds Assignment Name the following compounds using the prefix method: 1. CO ___________________________________ 2. CO2 ___________________________________ 3. SO2 ___________________________________ 4. NO2 ___________________________________ 5. N2O ___________________________________ 6. SO3 ___________________________________ 7. CCl4 ___________________________________ 8. NO ___________________________________ 9. N2O5 ___________________________________ 10. P2O5 ___________________________________ 11. N2O4 ___________________________________ 12. CS2 ___________________________________ 13. OF2 ___________________________________ 14. PCl3 ___________________________________ 15. PBr5 ___________________________________ 16. N2O3 ___________________________________ 17. PCl5 ___________________________________ 18. NH3 ___________________________________ 19. SCl6 ___________________________________ 20. SiO2 ___________________________________ 43 Name:_______________________________ Writing Formulas from Names Assignment Write the chemical formula for the compounds listed below: 1. Sodium chloride _____________________________ 2. Carbon tetrachloride ________________________ 3. Magnesium bromide ________________________ 4. Aluminum iodide ____________________________ 5. Hydrogen hydroxide _________________________ 6. Dihydrogen monoxide _______________________ 7. Iron (II) fluoride _____________________________ 8. Carbon dioxide ______________________________ 9. Sodium carbonate ___________________________ 10. Ammonium sulfide __________________________ 11. Magnesium sulfate ___________________________ 12. Dinitrogen pentoxide ________________________ 13. Phosphorous trichloride ____________________ 14. Copper (I) carbonate ________________________ 15. Potassium hydrogen carbonate _______________ 16. Sulfur trioxide _______________________________ 17. Ammonium phosphate _____________________ 18. Iron (II) oxide _______________________________ 19. Iron (III) oxide ______________________________ 20. Carbon monoxide ___________________________ 21. Calcium chloride ____________________________ 22. Potassium nitrate ___________________________ 23. Magnesium hydroxide _____________________ 24. Copper (II) sulfate __________________________ 25. Lead (IV) chromate _________________________ 26. Diphosphorous pentoxide _________________ 27. Potassium permagnate _____________________ 28. Sodium hydrogen carbonate ________________ 29. Zinc nitrate ___________________________________ 30. Aluminum sulfite ______________________________ 44 Name:_________________________________ Naming Acids Assignment Name the following acids: 1. HNO3 ___________________________________ 2. HCl ___________________________________ 3. H2SO4 ___________________________________ 4. H2SO3 ___________________________________ 5. HC2H3O2 ___________________________________ 6. HBr ___________________________________ 7. HNO3 ___________________________________ 8. H3PO4 ___________________________________ 9. H2S ___________________________________ 10. H2CO3 ___________________________________ Write the formulas of the following acids: 1. Sulfuric acid ___________________________________ 2. Nitric acid ___________________________________ 3. Hydrochloric acid ___________________________________ 4. Acetic acid ___________________________________ 5. Hydrofluoric acid ___________________________________ 6. Phosphorous acid ___________________________________ 7. Carbonic acid ___________________________________ 8. Nitrous acid ___________________________________ 9. Phosphoric acid ___________________________________ 10. Hydrosulfuric acid ___________________________________ 45 Name:___________________________________ Naming Organic Compounds Assignment 46 Name:___________________________________ Structure of Organic Compounds Assignment Ethane Ethyne Propane 3, 3-dimethyl pentane 2-butene 2, 3-dimethyl pentane Methane 1-butyne 47 Name:________________________ Types of Solids Assignment Determine if the following compounds are metallic solids, ionic solids, network atomic solids, molecular solids, or amorphous solids based on their properties. These are all actual chemical compounds. 1) This material forms crumbly crystals and has a melting point of 16.60 Celsius. It has a low density in solid form. _______________________________ (acetic acid) 2) This material forms very hard colorless crystals. It does not dissolve in water and burns at high temperatures. _______________________________ (diamond, C-C bond) 3) This material forms colorless crystals that have a melting point of 6610 C. It is hard, brittle, and dissolves well in water. _______________________________ (sodium iodide) 4) This material forms silver crystals that do not dissolve in water and have a melting point of 14140 C. This material is very hard and is not a good conductor of electricity. _______________________________ (silicon) 5) This material is hard and melts at a temperature of 16100 C. It dissolves only with difficulty in very reactive acids and doesn’t conduct electricity when molten. It forms colorless crystals. _______________________________ (quartz) 6) This material is soft and doesn’t form crystals. It has a melting point of 6600 C. It doesn’t dissolve in water. It is used as a structural material in the construction of airplanes and rockets. _______________________________ (aluminum) For chemistry help, visit www.chemfiesta.com © 2002 Cavalcade Publishing – All Rights Reserved 48