Final answer:
Ionic bonds are formed when electrons are completely transferred from one atom to another, while covalent bonds are formed when a pair of electrons is shared unequally by two atoms.
Step-by-step explanation:
Ionic bonds are formed when electrons are completely transferred from one atom to another. This results in the formation of positively charged cations and negatively charged anions, which are then attracted to each other due to their opposite charges.
Covalent bonds, on the other hand, are formed when a pair of electrons is shared unequally by two atoms. In covalent bonds, the participating atoms do not lose or gain electrons permanently, but rather share them in a mutually stabilizing relationship.
Therefore, the correct answer is b.electrons are completely transferred from one atom to another for ionic bonds and c.a pair of electrons is shared unequally by two atoms for covalent bonds.
Learn more about Ionic and Covalent Bonds