1.  boric acid = B(OH)₃   borax = Na₂B₄O₅(OH)₄^.8H₂O
    gypsum = CaSO₄.2H₂O  alumina = Al₂O₃

2.          (a)           (c)              (d)
           

 (b) because it has 6 valence electrons;

3.   borax, Na₂B₄O₅(OH)4^.8H₂O = Na₂B₄O₇^.10 H₂O
   kernite, Na₂B₄O₅(OH)4^.2H₂O = Na₂B₄O₇^.4 H₂O

4. bauxite, AlO(OH)

5. The Bayer process:

AlO(OH)(s) + NaOH(aq) + H₂O(l)  NaAl(OH)₄(aq)
SiO₂(s) + 2 NaOH(aq)  Na₂SiO₃(aq) + H₂O(l)
NaAl(OH)₄(aq)  Al(OH)₃(s) + NaOH(aq)
Al(OH)₃(s)   Al₂O₃(s) + H₂O
2 AlO(OH)   Al₂O₃ + H₂O
2 Al₂O₃   4 Al(l) + 3 O₂(g)

6.  6 HF + Al(OH)₃ + 3 NaOH   Na₃AlF₆ + 6 H₂O

7. It is the electrochemical process by which aluminum is obtained from alumina (Al₂O₃).  The Hall process involves the use of an artificial cryolite ore, Na₃AlF₆. which serves to lower the melting point of alimina:
 

Al₂O₃/Na₃AlF₆ + 3 e-   Al(l)

8. Boron is the only non-metal and there are no metalloids; Al, Ga, In, and Tl are all metals.

9. carbon, silicon

10.

11.  (a) Td (b) Oh (c) D3h (d) D2h

12.  Na = +1; B = +3; O = -2; H = +1

13. ability to conduct electricity, malleability, ductility, luster, etc.

14.
               Fe₂O₃(s) + 2 Al(s)   2 Fe(s) +  Al₂O₃
DHf         -822                0                         0         -1676
 

 DHrxn = -854 kJ

15.

 (a) 2 Ga(s) + 6 HCl(aq)   3 H₂(g) + 2 GaCl₃
 (b) 6 H₂O + 2 In(s) + 2 OH^-(aq)   3 H₂(g) + 2 [In(OH)₄]^-

16.
 

17. see a periodic table