Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which type of bond allows electrons to move freely among metals?

1. Ionic bonding

2. Covalent bonding

3. Metallic bonding

4. Hydrogen bonding

The correct answer is: Metallic bonding

Metallic bonding is characterized by a unique arrangement of atoms within a metal where electrons are not associated with any specific atom but rather form a 'sea of electrons' that are free to move throughout the structure. This delocalization of electrons allows metals to conduct electricity and heat effectively, as the free electrons can flow in response to an electric field or thermal energy. In contrast, ionic bonding involves the transfer of electrons from one atom to another, resulting in charged ions that attract each other. Covalent bonding entails the sharing of electron pairs between atoms, creating a strong bond but limiting electron mobility. Hydrogen bonding is a weak attraction between polar molecules and does not involve the type of electron movement found in metallic bonding. The properties resulting from metallic bonding, such as malleability and ductility, are also significant benefits, as the electron mobility allows the metal to be shaped without breaking.