Question

If an element, X, can form an oxide that has theformula X2O3, then element X would most likely be located on the Periodic Table in the same group as
(1) Ba (3) In
(2) Cd (4) Na

Answer 1

In! This is becasue it has a valency of 3

Answer 2

Answer: (3) In

Explanation: As the given compound is $X_2O_3$, it can be said that X has a valency of 3.

1)Barium (Ba): Atomic no: 56: $Xe6s^2$ : In order to complete its octet, it needs to donate 2 electrons, and thus the valency is 2.

2) Cadmium (Cd) : Atomic no: 48: $Kr5s^24d^{10}$ : In order to complete its octet, it needs to donate 2 electrons, and thus the valency is 2.

3) Indium (In): Atomic no: 49: $Kr5s^25p^{1}$ : In order to complete its octet, it needs to donate 3 electrons, and thus the valency is 3.

4) Sodium (Na): Atomic no: 11: $Ne3s^1$ : In order to complete its octet, it needs to donate 1 electron, and thus the valency is 1.

So the given element could only belong to the group containing Indium (In) as all the elements in the same group exhibit similar valency.