Question

Use Mendeleev's periodic table to predict the formula for the oxide of the following elements: K,C, Al, Si, Ba?

Answer 1

Answer:

Oxygen is a member of group VIA in Mendeleev’s periodic table. Its valency is 2. Similarly, the valencies of all the elements listed can be predicted from their respective groups. This can help in writing the formulae of their oxides.

Potassium (K) is a member of group IA. Its valency is 1. Therefore, the formula of its oxide is K2O.

Carbon (C) is a member of group IVA. Its valency is 4. Therefore, the formula of its oxide is C2O4 or CO2.

Aluminium (Al) belongs to groups IIIA and its valency is 3. The formula of the oxide of the element is Al2O3.

Silicon (Si) is present in group IVA after carbon. Its valency is also 4. The formula of its oxide is Si2O4 or SiO2.

Barium (Ba) belongs to group IIA and the valency of the element is 2. The formula of the oxide of the element is Ba2O2 or BaO.