Give an example in each of the following cases:(i) a divalent anion (valency 2)(ii) a trivalent cation (valency 3)

Divalent Anion Example

1. Definition: A divalent anion is an ion with a -2 charge, meaning it has gained two electrons.
2. Example: One common example of a divalent anion is the sulfate ion, represented as $\text{SO}_4^{2-}$.
   • It consists of one sulfur atom bonded to four oxygen atoms, and the overall charge is -2.

Trivalent Cation Example

1. Definition: A trivalent cation is an ion with a +3 charge, indicating it has lost three electrons.
2. Example: An example of a trivalent cation is the aluminum ion, represented as $\text{Al}^{3+}$.
   • It is formed when an aluminum atom loses three electrons, resulting in a net positive charge of +3.

These examples demonstrate the principles of ionic charges, where the valency indicates the charge magnitude based on the gain or loss of electrons.