ANSWER
2 valence electrons
STEP-BY-STEP EXPLANATION:
The electronic configuration is given below as

Looking at the configuration, you will see that the last energy carries 2 electrons
Hence, the valence electrons are 2
Answer:
Mg(OH)2
Explanation:
Magnesium hydroxide is the base since it has hydroxyl ions.
Answer:
Mass = 0.158 g
Explanation:
Formula used,
P V = n R T
Or,
n = P V / R T
Putting values,
n = 0.948 atm . 0.025 L / 0.0821 L.atm.K⁻¹.mol⁻¹ . 291.45
n = 0.00099 mol
Note: we have changed pressure from mmHg to atm, volume from mL to L and temperature from C to K)
Also,
Mass = n . Molecular Mass
Mass = 0.00099 mol × 159.808 g/mol
Mass = 0.158 g
Answer:
It can't be done.
Explanation:
If you have only 5.4 g of oxygen, the most lithium oxide you can get is 7.7 g.
Only 2.3 g of lithium will react. and the other 22.3 g of lithium will not be used.