Write the correct ionic formula when given two elements that bond ionically.

            Ionic bond is formed by the opposite ions attraction between the 2 atoms in an ionically bonded compound. The two ions i.e. Cation and Anions are formed by oxidation and reduction reactions respectively. General Ionic formula is as follow,

                                             Mⁿ⁺ + Nⁿ⁻   →  MN
where;
           Mⁿ⁺   =  Cation

           Nⁿ⁻   =  Anion

           MN  =  Salt

Explanation:
                   Ionic bond is the electrostatic forces of attraction between positively charged cations and negatively charged Anions. These forces are very stronger resulting in increasing several physical properties of Ionic compounds like melting point and boiling point e.t.c.

Example:

Sodium Chloride:
                           NaCl is formed by Na⁺ cation and Cl⁻ anion as follow,

Oxidation of Na;

                                      2 Na  →  2 Na⁺  +  2 e⁻
Reduction of Cl₂;

                                    Cl₂  +  2 e⁻  →  2 Cl⁻

Crystal Lattice formation is as follow,

                                  Na⁺  +  Cl⁻   →  NaCl

Ithink it’s 3 as the answer.

B. a graduated substance