Which of these elements would form an ionic bond between them?
a. cl and f
b. cl and cl
c. ca and br
d. ca and mg

Answer : The elements form an ionic bond will be, (C) Ca and Br

Explanation:

Ionic bond : It is defined as the bond that is formed by complete transfer of electrons from one atom to another atom.

That means, the atom which looses the electron is known as electropositive atom and the atom which gains the electron is known as electronegative atom.

The ionic bond is usually formed between a metal and a non-metal.

Covalent bond : It is defined as the bond which is formed when sharing of electrons takes place between the atoms.

This is usually formed between two non-metals.

(a) Chlorine  and fluorine

In this pair, fluorine is a non-metal and chlorine is also non-metal. So, chlorine and fluorine will form a covalent bond.

(b) Chlorine  and chlorine

In this pair, chlorine  is a non-metal. So, chlorine  and chlorine will form a covalent bond.

(c) Calcium and bromine

In this pair, calcium is a metal and bromine is a non-metal. So, calcium and bromine will form an ionic bond.

(d) Calcium and magnesium

In this pair, calcium and magnesium are metals. So, no bond form between calcium and magnesium.

Hence, the elements form an ionic bond will be, (C) Ca and Br

i just learnt this recently but i need to look through my notes again