Question

 Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, Al, Si, Ba.

Answer 1

K is in group 1. Therefore, the oxide will be K₂O.
C is in group 4. Therefore, the oxide will be CO₂.
Al is in group 3. Therefore, the oxide will be Al₂O₃.
Si is in group 4. Therefore, the oxide will be SiO₂.
Ba is in group 2. Therefore, the oxide will be BaO.