Which of the following statements is true about metallic solids?
They are formed by the sharing of electrons between atoms
They have high melting and boiling points due to strong covalent bonds
They are good conductors of electricity and heat
They have a random arrangement of atoms in a three-dimensional structure
The statement that is true about metallic solids is: "They are good conductors of electricity and heat."
Metallic solids are materials composed of metal atoms that have a special type of bonding called metallic bonding. In metallic bonding, the outermost electrons of metal atoms are delocalized or shared among all the atoms in the solid, forming a "sea" of electrons. This allows for the free flow of electrons throughout the solid, making metals excellent conductors of both electricity and heat.
Additionally, metallic solids have a unique crystal structure. Unlike covalent and ionic solids, which have repeating unit cells of fixed sizes and shapes, metallic solids have a "giant" or "infinite" crystal lattice. This means that the metal atoms are arranged in a repeating pattern throughout the solid, but the size of the unit cell is not fixed. Instead, the crystal lattice extends in all directions and has no definite boundaries.
Due to their unique structure and bonding, metallic solids have several important physical properties. They typically have high melting and boiling points, but this is not due to strong covalent bonds like in covalent solids. Rather, it is due to the strong metallic bonding between atoms. Metallic solids are also generally malleable and ductile, meaning they can be easily shaped and bent without breaking. This is because the delocalized electrons can move freely through the solid, allowing for atoms to shift positions without breaking bonds.
In summary, metallic solids are materials that have a unique crystal structure and bonding. They are excellent conductors of electricity and heat, and have several other important physical properties, such as high melting and boiling points and malleability.