Which type of bond forms when the electronegativities of bonded atoms are significantly different?

• A. Ionic
• B. Covalent
• C. Metallic
• D. Hydrogen

Answer: (A)

A large difference in electronegativity causes electrons to be transferred from the less electronegative atom to the more electronegative one, creating oppositely charged ions. These ions attract each other strongly through electrostatic forces, forming an ionic bond. This is why compounds like table salt (where sodium donates an electron to chlorine) are held together by ionic bonds.

If electronegativities are similar, atoms tend to share electrons rather than transfer them, leading to covalent bonds. Metallic bonding involves a lattice of metal atoms sharing a common sea of delocalized electrons, not a transfer between two reacting atoms. Hydrogen bonding is an intermolecular interaction that occurs when hydrogen is bonded to a highly electronegative atom and interacts with another electronegative atom—not a primary bond formed between two atoms.