Answer:
± 1 or ± 2
Step-by-step explanation:
Electrovalent bonds are chemical bonds that are established on the premise of transferring electrons between two atoms.
In this bond type, a higly electronegative atom, typically a non-metal receives electrons from an atom with lesser electronegativity, a metal.
To know the number of electrons involved in forming electrovalent bonds, we typically look at the groups of atoms that combines to form the bond.
Metals are found in group I and II on the periodic table. Metals are electropositive and are good electron donors. These metals have 1 and 2 electrons in their valence shell respectively. In like manners, the more electronegative atoms are found in group VI and VII. The elements in these groups are non-metals with high electronegativity and requires just 1 and 2 electrons to complete their octet.