Figure 1. I - Mg 2+ HS Chemistry POGIL Activity. metal with a non-metal with a with a

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1 HS Chemistry PGIL Activity Topic: Naming & Formula Writing 1(BW) Why? In this activity we will address the question: How do the smallest particles of matter connect to each other and how do we represent those connections by the names we give a substance? Figure 1 Particle model Ca2+ 2- Ca Ca Ca Ca Ca Periodic table location X Na Cl X metal with a non-metal with a with a Formula NaCl C 2 Ca Name sodium chloride carbon dioxide calcium oxide Particle model C C C C Mg 2+ Mg 2+ Mg Mg 2+ Mg 2+ Mg - I N N N N N N Periodic table location with a with a with a Formula C MgI 2 N 2 4 Name carbon monoxide magnesium iodide dinitrogen tetroxide

2 HS Chemistry PGIL Activity Page 2 1. In the particle models in Figure 1, what do the circles represent? 2. Where is sodium located on the periodic table? Where is chlorine located on the periodic table? Complete the periodic table location for all of the remaining elements found in each of the particle models in Figure How many sodium 1+ s are there in the particle model for NaCl? How many chlorine 1- s are there? Na : Cl 4. What is the simplest ratio of Na s to Cl s? 5. What is the smallest group of atoms called in the particle model of C 2? How many carbons? How many oxygens? 6. Do both C 2 and NaCl have the same type of elements (metal or non-metal) connected together? What is different about the C 2 particle model and the NaCl particle model (charges? connections of particles? etc ) 7. In what ways are the particle models of Ca and C 2 similar? How are they different? 8. Is C more similar to C 2 or Ca? Explain your answer and give specific evidence from Figure How many Mg 2+ s are there in the particle model for MgI 2? How many iodine 1- s are there? Mg : I What is the simplest ratio of Mg s to I s? 10. Why don t the formulas for NaCl, Ca, and MgI 2 have charges even though charges are in the particle models?

3 HS Chemistry PGIL Activity Page 3 Figure 2: a lattice a molecule Vocabulary for different ways particles are connected together. Ca2+ 2- Ca Ca Ca Ca Ca Ca calcium oxide C 2 carbon dioxide 11. What types of compounds arrange in a lattice structure versus in a molecule structure? Give specific evidence from Figure How is MgI 2 different from C 2? How is MgI 2 similar to C 2? 13. How many nitrogens and how many oxygens are in the smallest groupings of N 2 4? Why do you think one must write the formula N 2 4 and not simplify the formula to N 2 as was done with MgI 2? Explain how you made your decision from evidence in Figure a. Go back to Figure 1 and circle in any names where you see a prefix (di-, tri-, tetra-, etc ) used as part of the name? b. What are 2 things that make these compounds which are named with prefixes unique? 15. Would you use prefixes to name KI? Why or why not? 16. Specify which of the following compounds would be named using prefixes and which would not: Compound Name with Reason Compound Name with Reason prefixes? Y or N prefixes? Y or N C 2 Yes, use NaCl prefixes CaCl 2 P 2 5 N 2 6 RbBr CuCl 2 AgCl XeF 6 BF 3

4 HS Chemistry PGIL Activity Page 4 The Greek prefixes: mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- undeca- dodeca- When you have a compound that needs to be named using prefixes, you choose the prefix which specifies the number atoms of that element in the molecule and add an -ide ending to the second element. The only except is that you never use mono- on the first element. Examples: N 2 4 was named dinitrogen tetroxide (meaning there are 2-nitrogens and 4 oxygens) C was named carbon monoxide (meaning 1 carbon with 1 oxygen atom) NT monocarbon monoxide Name the following compounds 14. Si S 4 N Cl PF 3 Write formulas for the following compounds. 18. sulfur trioxide 19. carbon tetrachloride 20. diphosphorous pentoxide 21. sulfur hexafluoride

5 HS Chemistry PGIL Activity Page 5 n your own Naming Compounds with prefixes Write the formulas for the following covalent compounds: 1) antimony tribromide 2) dinitrogen pentoxide 3) chlorine dioxide 4) hydrogen iodide 5) iodine pentafluoride 6) tetrasulfur tetranitride 7) ammonia (need to memorize this one-doesn t follow naming rules) 8) phosphorus triiodide Write the names for the following covalent compounds: 9) P 4 S 5 10) 2 11) SeF 6 12) Si 2 Br 6 13) SCl 4 14) CH 4 (common name: ) 15) P 3 I 5 16) NF 3

6 HS Chemistry PGIL Activity Page 6 Teacher Resources Prior knowledge needed for this activity: This activity assumes that: o students are able to identify elements as being either a metal or non-metal based upon the element s position on the periodic table o students are able to distinguish between atoms and molecules on a particulate representation/model of matter Thoughts on presentation of the activity: Make sure students have an individual copy of the periodic table at the start of the activity I have included some suggested points which seem to be important for verifying understanding before allowing groups to move forward. These spots are marked with a: Target Responses for the tasks:

7 HS Chemistry PGIL Activity Page 7 Target Responses for the tasks: 1. In the particle models in Figure 1, what do the circles represent? Each circle represents an atom. Different elements are represented by their symbol inside each circle 2. Where is sodium located on the periodic table? Where is chlorine located on the periodic table? Sodium is located on the left side which means sodium a metal, chlorine is found on the right side of the periodic table which means Cl is a non-metal Complete the periodic table location for all of the remaining elements found in each of the particle models in Figure 1. (make sure students do this step!) 3. How many sodium +1 s are there in the particle model for NaCl? How many chlorine -1 s are there? 12 Na : 12 Cl 4. What is the simplest ratio of Na s to Cl s? Na:Cl = 1:1, written as NaCl 5. What is the smallest group of atoms called in the particle model of C 2? A molecule How many carbon s? 1 carbon How many oxygens? 2 oxygens 6. Do both C 2 and NaCl have the same type of elements (metal or non-metal) connected together? What is different about the C 2 particle model and the NaCl particle model (charges? connections of particles? etc ) No, C 2 has only non-metal elements connected to non-metal elements. C 2 exists as small groups of 1 carbon connected to 2 oxygens (a molecule) while NaCl exists as a repeating patter of s and s, C 2 does not have any charges while NaCl has charges that balance out to In what ways are the particle model of Ca similar or different to C 2? Similar: both Ca and C 2 have oxygen as one of the elements Differences: C2 does not have any charges, Ca exists as a repeating pattern of charged particles while C 2 has no charges on any atoms and exists in a molecular forml 8. Is C more similar to C 2 or Ca? Explain your answer and give specific evidence from Figure 1. Though C and Ca are more similar in chemical formula (both a 1:1 ratio), C is more similar to C 2 because both are non-metals connected to non-metals, C and C 2 and both exist in the molecular form not in a lattice structure. 9. How many Mg +2 s are there in the particle model for MgI 2? How many iodine -1 s are there? 6 Mg : 12 I What is the simplest ratio of Mg s to I s? 1 Mg to 2 I s, MgI Why don t the formulas for NaCl, Ca, and MgI 2 have charges even though charges are found in the particle models? The charges balance out so there is no need to write the charge as part of the formula.

8 HS Chemistry PGIL Activity Page 8 Figure 2: a lattice a molecule Vocabulary for different ways particles are connected together. Ca2+ 2- Ca Ca Ca Ca Ca Ca calcium oxide C 2 carbon dioxide 10. What types of compounds arrange in a lattice structure versus in a molecule structure? Give specific evidence from Figure 1. metals connected to non-metals form a compound which will have charges in a lattice structure whereas non-metals connected with another non-metal will exist as a molecule. 11. How is MgI 2 different from C 2? How is MgI 2 similar to C 2? MgI 2 is a metal with a non-metal both have a 1:2 ratio of types of atoms MgI 2 exists in a lattice structure while C2 exists in a molecular form. 12. How many nitrogens and how many oxygens are in the smallest groupings of N 2 4? 2 nitrogens, 4 oxygens Why do you think one must write the formula N 2 4 and not simplify the formula to N 2 as was done with MgI 2? Explain how you made your decision from evidence in Figure 1. Since N 2 4 is a compound which is made of non-metal with a non-metal the substance exists as a molecule so you must show how many of each atoms are actually in the molecule, thus you can t reduce to just the ratio like is done when the substance exists in a lattice structure 13. a. Go back to Figure 1 and circle in any names where you see a prefix (di-, tri-, tetra-, etc ) used as part of the name? b. What are 2 things that make these compounds which are named with prefixes unique? Compounds named with prefixes 1) don t have charges 2) are non-metals connected to non-metals 3) exist as molecules NT lattices 14. Would you use prefixes to name: KI? Why or why not? No. This is a metal with a non-metal so there will be charges which balance out and will exist in a lattice structure NT as a molecule. 15. Specify which of the following compounds would be named using prefixes and which would not: Compound Name with Reason Compound Name with Reason prefixes? Y or N prefixes? Y or N C 2 Yes, use NaCl No prefixes CaCl 2 No P 2 5 Yes N 2 6 Yes RbBr No CuCl 2 No AgCl No XeF 6 Yes BF 3 Yes

9 HS Chemistry PGIL Activity Page 9 The Greek prefixes: mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- undeca- dodeca- When you have a compound that needs to be named using prefixes, you choose the prefix which specifies the number atoms of that element in the molecule and add an -ide ending to the second element. The only except is that you never use mono- on the first element. Examples: N 2 4 was named dinitrogen tetroxide (meaning there are 2-nitrogens and 4 oxygens) C was named carbon monoxide (meaning 1 carbon with 1 oxygen atom) NT monocarbon monoxide Name the following compounds 22. Si 2 silicon dioxide 23. S 4 N 2 tetrasulfur dinitride 24. Cl 2 dichlorine monoxide 25. PF 3 phosphorus trifluoride Write formulas for the following compounds. 26. sulfur trioxide S carbon tetrachloride CCl diphosphorous pentoxide P sulfur hexafluoride SF 6

10 HS Chemistry PGIL Activity Page 10 n your own Naming Compounds with prefixes Write the formulas for the following covalent compounds: 1) antimony tribromide SbBr 3 2) dinitrogen pentoxide N 2 5 3) chlorine dioxide Cl 2 4) hydrogen iodide HI 5) iodine pentafluoride IF 5 6) tetrasulfur tetranitride S 4 N 4 7) ammonia NH 3 8) phosphorus triiodide PI 3 Write the names for the following covalent compounds: 9) P 4 S 5 tetraphosphorus pentasulfide 10) 2 oxygen 11) SeF 6 selenium hexafluoride 12) Si 2 Br 6 disilicon hexafluoride 13) SCl 4 sulfur tetrachloride 14) CH 4 methane 15) P 3 I 5 triphosphorus pentaiodide 16) NF 3 nitrogen trifluoride