We are given that the element Z has a valency of 3. The oxide ion is denoted by O2- and has a valency of 2. So in order to find the chemical formula of the compound, we will cross over the valencies of the two combining atoms. Thus the chemical formula of the substance will be Z2O3. 

Valency of Element Z

The valency of an element indicates the number of electrons an atom of that element can gain, lose, or share in order to achieve a stable electron configuration. In this case, element Z has a valency of 3.

Formula of Oxide of Z

The formula of an oxide can be determined by considering the valency of the element and the charge of the oxygen ion. Oxygen typically has a valency of -2, meaning it tends to gain two electrons to achieve stability.

To find the formula of the oxide of element Z, we need to balance the charges of Z and oxygen. Since Z has a valency of 3, it tends to lose three electrons to achieve stability. On the other hand, oxygen has a valency of -2, so it tends to gain two electrons.

Balancing Charges

To balance the charges, we need to find the least common multiple (LCM) of the valencies of Z and oxygen. The LCM of 3 and 2 is 6.

Formula of Oxide of Z

To balance the charges, we need two oxygen ions for every three Z ions. Therefore, the formula of the oxide of Z is Z2O3.

Explanation

The formula Z2O3 indicates that there are two Z ions and three oxygen ions in the compound. The valency of Z is 3, so two Z ions with a total charge of +6 balance the three oxygen ions with a total charge of -6.

The oxide of Z, Z2O3, represents a compound where two Z atoms are combined with three oxygen atoms. This compound is electrically neutral due to the balanced charges.

Conclusion

In summary, the formula of the oxide of element Z, which has a valency of 3, is Z2O3. This formula represents a compound where two Z ions are combined with three oxygen ions to achieve electrical neutrality.

Z2O3