Beryllium chlorite is formed when a beryllium cation with charge 2+ combines with a chlorite ion with charge 1-. how will you derive the formula for beryllium chlorite?

The formula for beryllium chlorite is Be(ClO2)2.

The beryllium cation has a charge of 2+ and a chlorite ion has a charge of 1-. Using the crisscross method, we move the charge of the beryllium cation to the subscript position of the chlorite ion and the charge of the chlorite ion to the subscript position of the beryllium cation. So, we get Be1(ClO2)2. The ratio one-to-two cannot be reduced further. Since the subscript of Be is 1, we drop it and get Be(ClO2)2.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.