1. Class work, discussion
   
   1. Collect Ch. 3 homework.
      
   2. Review "dozens" problem with molecular models.
      
   3. Problem: How can salt solutions be compared on the basis of the number of molecules they contain?
      
                      "dozen" = 12 of anything
      
      But a dozen molecules of any kind is such a small mass that their behaviour can not be measured. To be able to measure the behaviour of molecules with most common instruments, a much larger number of them is needed.
      
                      "mole" = 6.02 x 10²³ of anything
      
      How does a mole of a substance relate to its mass?
      
              By definition: 1 mole of ¹²C (6 protons + 6 neutrons) has a mass of 12 grams.
      
              (This means that 6.02 x 10²³ C atoms has a mass of 12 grams)
      
      Basic ideas of periodic table -
      
      
      

      1	- atomic number =# protons in the nucleus (also = # of electrons)
      H
      1.008	- atomic mass = the mass of one mole (6.02 x 1023 atoms) of this     element

      
      
      
   4. Students are to make a reasonable guess as to the structures of the first 20 elements of the periodic table given the information above, a periodic table and the examples below (finish for homework) -
      
      

   atom	atomic number	atomic mass     (grams/mole)	# protons	structure     # neutrons	# electrons
   H	1	1.008	1	0	1
   He	2	4.003	2	2	2
   Li	3	6.94	3	4	3
   Be	4	9.012	4	5	4

   
   (students to continue...)
   
   
   
2. Do LAB 2.
   
   
3. Homework
   
   • finish the table
     
   • finish write-up of LAB 2
     
   • redo the "dozens" exercise of DAY 1 but substitute "moles" for "dozens". Also, use the periodic table to calculate the mass of each compound given the # of moles in part 3a.
     
   
   

AE Partners Collection Index

Activities Exchange Index