What is an electrovalent bond (or ionic bond)? Explain its formation with two suitable examples?

An element $\mathrm{A}$  combines with element $\mathrm{B}$. An atom of A contains two electrons in its outermost shell whereas that of $\mathrm{B}$ has $6$ electrons in its outermost shell. Two electrons are transferred from atom $\mathrm{A}$ to atom $\mathrm{B}$. What is the electronic structure of  $\mathrm{AB}$?

An element $\mathrm{A}$ combines with element $\mathrm{B}$. An atom of $\mathrm{A}$ contains two electrons in its outermost shell whereas that of $\mathrm{B}$ has $6$ electrons in its outermost shell. Two electrons are transferred from atom $\mathrm{A}$ to atom $\mathrm{B}$. What is the electrovalency of $\mathrm{A}$ and that of $\mathrm{B}$?