K- K2O
C- C2O4 or CO2
Al- Al2O3
Si- Si2O4 or SiO2
B – Ba2O2 or BaO
Group VI A of Mendeleev\’s periodic table is where oxygen belongs. The value of it is 2. All of the elements listed can also have their valencies inferred from the groups to which they belong. This will make it easier to write down their oxides\’ formulas.
(I) The element potassium (K) belongs to group IA. It has a value of 1. Its chemical composition is K2O.
(ii) Group IV A includes carbon (C). It has a value of 4. Consequently, the equation is C2O4 or CO2.
(iii) The valency of aluminium (Al), which is in group III A, is three. Its oxide has
the chemical formula Al2O3.
(iv) After carbon, silicon (Si) is found in group IV A. It also has a valency of 4. Oxide has the chemical formula Si2O4 or SiO2.
(v) Barium (Ba) belongs to group II A and the valency of the element is 2. The formula of the oxide of the element is Ba2O2 or BaO.