Determine whether the following pairs of elements can form ionic compounds.

a. oxygen and calcium

b. lithium and fluorine

c. potassium and calcium

d. nickel and chlorine

e. fluorine and sodium

f. sulfur and bromine

Answer:a) oxygen and calcium

b. lithium and fluorine

d. nickel and chlorine

e. fluorine and sodium

Explanation:

Ionic compounds are formed when there is complete transfer of electrons from a metal to a non-metal.

Covalent compounds are formed when sharing of electrons between two elements.

a) oxygen and calcium: In this calcium is a metal having + 2 oxidation state and oxygen is a non metal having - 2 oxidation state. This results in the formation of an ionic compound.

b) Lithium and fluorine : In this, Lithium is a metal having + 1 oxidation state and Fluorine is a non-metal having - 1 oxidation state which results in the formation of an ionic compound.

c) potassium and calcium will not result in the formation of ionic compound because both the elements are metals.

d) nickel and chlorine: In this, nickel is a metal having + 2 oxidation state and chlorine is a non-metal having - 1 oxidation state which results in the formation of an ionic compound.

e) fluorine and sodium: In this, sodium is a metal having + 1 oxidation state and Fluorine is a non-metal having - 1 oxidation state which results in the formation of an ionic compound.

f) sulfur and bromine : will not result in the formation of ionic compound because both the elements are non metals.