1.
Groups 2A - 4A Elements

2. Group 2A Alkaline Earth Metals (M) ns2 M2+ cations basic oxides
MOH + H2O → M2+ + 2OH-

3. Beryllium small size, high electronegativity amphoteric
Be(H2O) OH- → Be(H2O)2(OH)2 + 2H2O
BeCl2 - covalent

4. 2A Applications
Ca and Mg
human minerals
metal alloys
“hard” water

5. Group 3A ns2np1 B- only nonmetal in the group
borane - covalent hydrides (no BH3) that are highly reactive
Al - metallic properties but covalent bonds (amphoteric)
Ga - expands when frozen, largest liquid range for metals, amphoteric

6. Group 4A ns2np2 can form four covalent bonds with nonmetals C=life
forms π bonds: carbon backbones
CO, CO2, C3O2
Si = abundant semimetal
semiconductors, alloys, etc

7. Sample Exercise
Calculate the amount of time required to produce 1.oo x 103 kg of Mg by electrolysis of molten MgCl2 using a current of 1.00 x 102 A.
faraday = C
mol e-
A = C/s

8. 19.2 Practice
What mass of barium is produced when molten BaCl2 is electrolyzed by a current of x 105 A for 6.00 hrs?
faraday = C
mol e-
A = C/s

9. 19.3 Practice
Ga2O3 is an amphoteric oxide, and In2O3 is a basic oxide. Write equations for the reactions that illustrate these properties.

10. 19.4 Practice (Bio!)
The fermentation of glucose produces ethanol and carbon dioxide. Write a balanced equation for this process.