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