An element from group 2 on the periodic table will bond ionically with elements from group 17 (7A).

a) Choose an element from each of these groups and write the chemical formula for the compound they create.

b) Explain how the ionic bond is created between these two elements.

The answer to your question is below

Explanation:

a) I will choose three elements of each group

   Group IIA              Group VIIA            Formula

        Mg         +                F                       MgF₂            

        Ca          +                Cl                      CaCl₂

        Sr           +                 Br                      SrBr₂

b) Elements in group IIA have 2 electrons in their outermost shell so they can donate these electrons of group VII A which have seven electrons in their outermost shell. So it is necessary 2 elements of group VII A, each atoms accepts one electron.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.