Page 311.  Review and Practice                       Nov. 1

1.   Periodic Law:

 there are reoccurrences of chemical properties as you increase the mass  … leading to organization by groups.

2.  Contain metals – Group 1-Alkali metals,

                                  Group 2- Alkaline Earth metals

Non – metals -  Group 17 -Halogens,

                           Group 18 - Noble Gases,

                           Group 16 –

3.   .2Cs (s)  + 2H₂O (l)  à   H₂ (g)  + 2 CsOH (aq)

4.   Use rules of

     Group 1 Combining Capacity/Valence =  1 = lose 1 e^-        s¹

     Group 2 ……………………………...=  2  = lose 2 e^-                  s²

     Group 16 ………………….................= -2 = gain 2 e-        p⁴

     Group 17 …………..……………….. = -1 = gain 1 e-            p⁵

     Group 18 ……………..…………….  = 0  = stable              p⁶

a.  SrH₂

b.  SeH₂    (note two non-metals implies a covalent compound)

                Se has 6 valence electrons allowing for two sharing pairs with Hydrogen)

.. If you used your P.T. rules and the idea that H can be -1 or +1

 you would have written

     H₂Se

c.  HI

d.  RbF

e.  GaF₃  (note Ga is in group 13 so its valence/CC is 3+)

f.   TeF₂    (note two non-metals implies covalent compound)

_{…. could only do this using Lewis Dot structure (overlapping valence electrons)}

Notes

Which elements form diatomic molecular elements?  X₂

HOFBrINCl, 

If you find the seven they make a seven shape on the PT,

“I Bring Clay For Our New House”