Question

Lead is much softer than aluminum, and can be more easily deformed or pulled into a wire. What difference between the two materials best explains this? (a) Pb and Al atoms have different sizes. (b) Pb and Al atoms have different masses. (c) The stiffness of the interatomic bonds is different in Pb and Al.

Short answer

The reason for lead being softer than aluminum is that the stiffness of the interatomic bonds is different in Pb and Al.

Step-by-step solution

Given data:

Lead is much softer than aluminum, and can be more easily deformed or pulled into a wire.

Malleability:

A malleable material is one that can easily be formed into a thin sheet by hammering or rolling. In other words, the material has the ability to deform under compressive stress.

Malleability depends on interatomic bonds.

Determining the reason for lead getting more easily deformed than aluminum:

Stiffness means how long and easily a metal can take any shape by applying some force or pressure on it.

Stiffness generally depends on the following parameters:

1. Higher interatomic distance is directly proportional to the stiffness.
2. Low intermolecular bond is directly proportional to the stiffness.

Since lead has lower interatomic bond strength than aluminum, it is more malleable and thus can get more easily deformed.

Hence, option (c), the stiffness of the interatomic bonds is different in Pb and Al, is the correct answer.