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Forming Ionic Compounds A drena McDonald Venture Alternative High School. Before We Begin. Cut out the ions from your student worksheets. Have a glue stick ready to attach the ions to your compound worksheet. Now, let’s do the first few together. B +3. Boron (B +3 ) + Chlorine (Cl -1 )
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Forming Ionic CompoundsAdrena McDonaldVenture Alternative High School
Before We Begin • Cut out the ions from your student worksheets. • Have a glue stick ready to attach the ions to your compound worksheet. • Now, let’s do the first few together.
B+3 • Boron (B+3) + Chlorine (Cl-1) • 1 boron atom for every 3 chlorine atoms • 1. BCl3 Cl-1 Cl-1 Cl-1 boron chloride BCl3
2. Magnesium (Mg+2) + Chlorine (Cl-1) 1 magnesium atom for every 2 chlorine atoms 2. MgCl2 Cl-1 Cl-1 Mg+2 magnesium chloride MgCl2
3. Sodium (Na+1) + Chlorine (Cl-1) 1 sodium atom for every 1 chlorine atom 3. NaCl Cl-1 sodium chloride NaCl Na+1
4. Calcium (Ca+2) + Sulfur (S-2) 1 calcium atom for every 1 sulfur atom 4. CaS Ca+2 calcium sulfide CaS S-2
5. Aluminum (Al+3) + Nitrogen (N-3) 1 aluminum atom for every 1 nitrogen atom 5. AlN N-3 Al+3 aluminum nitride AlN
Now, it’s your turn. Do the remaining questions on your own.
6. Calcium (Ca+2) + Bromine (Br-1) 1 calcium atom for every 2 bromine atoms 6. CaBr2 Br-1 Br-1 Ca+2 calcium bromide CaBr2
7. Potassium (K+1) + Chlorine (Cl-1) 1 potassium atom for every 1 chlorine atom 7. KCl Cl-1 potassium chloride KCl K+1
B+3 B+3 8. Boron (B+3) + Oxygen (O-2) 2 boron atoms for every 3 oxygen atoms 8. B2O3 O-2 O-2 O-2 boron oxide B2O3
9. Magnesium (Mg+2) + Oxygen (O-2) 1 magnesium atom for every 1 oxygen atom 9. MgO Mg+2 magnesium oxide MgO O-2
10. Aluminum (Al+3) + Fluorine (F-1) 1 aluminum atom for every 3 fluoride atoms 10. AlF3 Al+3 F-1 F-1 F-1 aluminum fluoride AlF3
11. Potassium (K+1) + Iodine (I-1) 1 potassium atom for every 1 iodine atom 11. KI I-1 potassium iodide KI K+1
12. Sodium (Na+1) + Nitrogen (N-3) 3 sodium atoms for every 1 nitrogen atom 12. Na3N N-3 sodium nitride Na3N Na+1 Na+1 Na+1
13. Potassium (K+1) + Bromine (Br-1) • 1 potassium atom for every 1 bromine atom • 13. KBr Br-1 potassium bromide KBr K+1
14. Lithium (Li+1) + Fluorine (F-1) 1 lithium atom for every 1 fluorine atom 14. LiF F-1 lithium fluoride LiF Li+1
15. Magnesium (Mg+2) + Nitrogen (N-3) 3 magnesium atoms for every 2 nitrogen atoms 15. Mg3N2 N-3 N-3 Mg+2 Mg+2 Mg+2 magnesium nitride Mg3N2
Boron (B+3) + Chlorine (Cl-1) boron chloride • You can also determine the formula for a compound using the “criss-cross” method. Take the numbers from the ions’ superscripts and cross them to become the subscripts in the compound. Look at question #1. B+3 Cl-1 3 1 B Cl 3 1 BCl3
Magnesium (Mg2+) + Nitrogen (N-3) Magnesium nitride • Look at #15 to practice the “criss-cross” method again. Mg+2 N-3 2 3 Mg N 2 3 Mg3N2
Potassium (K+1) + Sulfate (SO4-2) potassium sulfate • This also works for polyatomic ions. K+1 (SO4)-2 1 2 K (SO4) Parentheses are not used unless a subscript is needed after the polyatomic ion, as you will see in the next example. K2SO4
Aluminum (Al+3) + Sulfate (SO4-2) aluminum sulfate • Use parentheses to indicate that more than one of the same polyatomic ion is included in the compound. Al+3 (SO4)-2 3 2 Al (SO4) Al2(SO4)3
If the superscript charges add to zero, DO NOT criss-cross. All compounds have a zero charge, so it takes one of each ion to make the compound: • Ca+2 + O-2CaO • B+3 + N-3 BN (+2 and -2 = 0) (+3 and -3 = 0)
Released TAKS Question calcium (Ca+2) + chlorine (Cl-1) calcium chloride The chemical formula for calcium chloride is --- A) Ca2Cl B) CaCl C) CaCl2 D) Ca2Cl3 Ca+2Cl-1 2 1 Ca Cl 2 1 CaCl2
Released TAKS Question Al3+ SO42- According to this information, what is the chemical formula for aluminum sulfate? A) AlSO4 B) Al2(SO4)3 C) Al3(SO4)2 D) Al6SO4 Al+3 (SO4)-2 3 2 Al (SO4) Al2(SO4)3
Questions? • Good job!!! • Don’t forget to put your name on your paper before you turn it in.
B+3 Cl-1 Mg+2 N-3 Cl-1 K+1 Br-1 Br-1 I-1 Cl-1 Mg+2 Ca+2 F-1 N-3 O-2 Al+3 Ca+2 Mg+2 O-2 P-3 Li+1 Na+1 Mg+2 F-1 Al+3 O-2 S-2 Na+1 Ca+2 F-1 K+1 P-3 S-2 B+3 Na+1 K+1 Br-1 Cl-1
Write the chemical formula for the following compounds. Place the cutouts in the corresponding boxes on the following pages. • Boron (B+3) + Chlorine (Cl-1) boron chloride ____________ • Magnesium (Mg+2) + Chlorine (Cl-1) magnesium chloride ____________ • Sodium (Na+1) + Chlorine (Cl-1) sodium chloride ____________ • Calcium (Ca+2) + Sulfur (S-2) calcium sulfide ____________ • Aluminum (Al+3) + Nitrogen (N-3) aluminum nitride ____________ • Calcium (Ca+2) + Bromine (Br-1) calcium bromide ____________ • Potassium (K+1) + Chlorine (Cl-1) potassium chloride ____________ • Boron (B+3) + Oxygen (O-2) boron oxide ____________ • Magnesium (Mg+2) + Oxygen (O-2) magnesium oxide ____________ • Aluminum (Al+3) + Fluorine (F-1) aluminum fluoride ____________ • Potassium (K+1) + Iodine (I-1) potassium iodide ____________ • Sodium (Na+1) + Nitrogen (N-3) sodium nitride ____________ • Potassium (K+1) + Bromine (Br-1) potassium bromide ____________ • Lithium (Li+1) + Fluorine (F-1) lithium fluoride ____________ • Magnesium (Mg+2) + Nitrogen (N-3) magnesium nitride ____________
1. B+3 + Cl-1 2. Mg+2 + Cl-1 3. Na+1 + Cl-1 4. Ca+2 + S-2
5. Al+3 + N-3 6. Ca+2 + Br-1 7. K+1 + Cl-1 8. B+3 + O-2
9. Mg+2 + O-2 10. Al+3 + F-1 11. K+1 + I-1 12. Na+1 + N-3
13. K+1 + Br-1 14. Li+1 + F-1 15. Mg+2 + N-3
Key • Boron (B+3) + Chlorine (Cl-1) boron chloride _____BCl3 _____ • Magnesium (Mg+2) + Chlorine (Cl-1) magnesium chloride ____ MgCl2 _____ • Sodium (Na+1) + Chlorine (Cl-1) sodium chloride _____NaCl _____ • Calcium (Ca+2) + Sulfur (S-2) calcium sulfide _____CaS _____ • Aluminum (Al+3) + Nitrogen (N-3) aluminum nitride _____AlN ______ • Calcium (Ca+2) + Bromine (Br-1) calcium bromide ____CaBr2 ______ • Potassium (K+1) + Chlorine (Cl-1) potassium chloride _____KCl _______ • Boron (B+3) + Oxygen (O-2) boron oxide ____ B2O3 _______ • Magnesium (Mg+2) + Oxygen (O-2) magnesium oxide _____MgO ______ • Aluminum (Al+3) + Fluorine (F-1) aluminum fluoride _____AlF3 ______ • Potassium (K+1) + Iodine (I-1) potassium iodide _____ KI_______ • Sodium (Na+1) + Nitrogen (N-3) sodium nitride ____Na3N ______ • Potassium (K+1) + Bromine (Br-1) potassium bromide _____KBr _______ • Lithium (Li+1) + Fluorine (F-1) lithium fluoride _____ LiF ________ • Magnesium (Mg+2) + Nitrogen (N-3) magnesium nitride ____Mg3N2 ______
Notes to Teacher • If you want to have the students cut out the ions themselves, they will need two copies of the ion sheet to complete the assignment. • In order to save time you may want to try having the students cut out the ions as homework. • If you are a paper-saving type, you can make class sets of ions (just one sheet per student since they can reuse ions) and not have the students actually paste them on the answer sheets. Instead, you can: • Have a class set of ions premade and laminated. Put them in ziploc bags to keep them separate. You can also laminate a class set of answer sheets if you want the students to have a reusable place to work out their solutions. • Print the ion pages on magnetic paper and cover it with adhesive laminate prior to cutting out the pieces. Then place these sets in ziploc bags. Students can rearrange the ions on whiteboards or cheap cookie tins (which can be purchased at most dollar stores) before writing down their answers.