Question

Chemical names and formulas by using criss cross method

Answer 1

Criss Cross method is a simple method used to write the chemical formulas of a  given compound.

Step 1: Write the Symbols of elements present in compounds
Sodium Choride
Na            Cl

Step 2:  Write the valencies at the top of the symbols

Na ¹           Cl¹

Step 3:
Criss cross the valency
Na ¹           Cl¹

Na             Cl

Example 2 :
Magnesium Chloride

Step 1: Mg       Cl

Step 2: Mg²     Cl¹

Step 3:  Mg²     Cl¹
             
              Mg     Cl2
Hence magnesium chloride formula is MgCl2