International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What characteristic allows metals to be ductile and malleable?

1. Atoms form covalent bonds

2. Layers of atoms that can slide over each other

3. Presence of strong ionic bonds

4. High density of metals

The correct answer is: Layers of atoms that can slide over each other

Metals are characterized by their ability to be ductile and malleable due to the arrangement of their atoms, which allows layers of atoms to slide over each other. In metallic bonding, atoms are held together by a "sea of electrons" that are not bound to any specific atom. This structure means that when force is applied, the layers of atoms can shift without breaking the overall metallic structure. This unique property is fundamental to metals; it enables them to be drawn into wires (ductility) and hammered into thin sheets (malleability). If a material lacked this capability, it would likely shatter or crack under stress rather than deform. The other choices do not accurately represent the reason for ductility and malleability in metals. Covalent bonds are typically found in non-metallic compounds and do not allow for the sliding of layers. Strong ionic bonds create rigid structures that are brittle, which is the opposite of malleability and ductility. While high density can be a characteristic of metals, it does not directly influence their ability to deform under stress. Thus, the key to ductility and malleability lies specifically in the ability of metal atoms to slide over one another.