Question

Which would you expect to be the more ductile element, (a) Ag or Mo, (b) Zn or Si? In each case explain your reasoning.

Short answer

In summary, (a) Ag (Silver) is expected to be more ductile than Mo (Molybdenum) due to its higher ductility, malleability, and weaker metallic bonding; (b) Zn (Zinc) is expected to be more ductile than Si (Silicon) due to its metallic properties as compared to Si being a metalloid, which exhibits more brittle behavior.

Step-by-step solution

Consider the periodic table classification

First, identify whether the given elements are metals or non-metals, as ductility is generally a property of metals. Ag and Mo are both classified as metals, while Zn is a metal and Si is a metalloid.

Examine the metallic properties of Ag and Mo.

Silver (Ag) is a transition metal, while Molybdenum (Mo) belongs to the group of refractory metals. Silver possesses higher ductility and malleability compared to Molybdenum. Moreover, the metallic bonding in Ag is relatively weaker than in Mo, making it easier for Ag atoms to slide past one another.

Compare the ductility for pair (a)

Based on the metallic properties, we can conclude that Ag (Silver) is expected to be more ductile than Mo (Molybdenum) in pair (a).

Examine the metallic properties of Zn and Si.

Zinc (Zn) is a metal that appears in the group of post-transition metals, while Silicon (Si) is a metalloid. Zinc exhibits metallic properties like ductility and malleability, whereas Silicon, being a metalloid, exhibits a more brittle behavior.

Compare the ductility for pair (b)

Since ductility is generally a property of metals, we can conclude that Zn (Zinc) is expected to be more ductile than Si (Silicon) in pair (b). In summary, it is expected that Silver (Ag) and Zinc (Zn) are the more ductile elements in their respective pairs due to their metallic properties and periodic table classifications.

Key concepts

Periodic Table Classification

Understanding the periodic table classification is vital when comparing the ductility of elements. The periodic table is organized into groups and periods that represent elements with shared characteristics. Metals, nonmetals, and metalloids are the primary types of elements, each holding unique properties.

Metals, found on the left side and center of the table, are typically ductile, malleable, and excellent conductors of electricity and heat. In the exercise, Ag (Silver) and Mo (Molybdenum) are metals, while Zn (Zinc) is also a metal with Si (Silicon) classified as a metalloid. Metalloids like Si have properties intermediate between metals and non-metals, which often include lower ductility compared to metals.

This classification supports the reasoning in the textbook exercise that metals are expected to exhibit greater ductility due to their inherent metallic characteristics.

Metallic Bonding

The concept of metallic bonding explains why metals like Ag and Zn are ductile. Metallic bonding involves the free movement of electrons within a lattice of metal cations. These 'sea of electrons' allow the atoms to slide past each other without breaking bonds, a property intrinsic to ductile materials.

In the case of Ag versus Mo, the metallic bonding in Ag is weaker, which facilitates the movement of atoms and contributes to its higher ductility. Stronger bonds in Mo, a refractory metal, make it less ductile than Ag. In simpler terms, the looser the electrons are within the metallic structure, the easier it is for the material to be shaped and extended, which is the essence of ductility.

Metals vs Metalloids

When distinguishing between metals and metalloids, the most notable difference is their physical properties, often highlighted by their ductility. Metals are generally more malleable and ductile, appropriate for numerous applications requiring material deformation without fracturing.

Metalloids, on the other hand, have a mixed bag of characteristics that lie between metals and non-metals. Silicon (Si), a typical metalloid, has a more intricate crystalline structure which hinders the sliding of layers, leading to brittleness rather than ductility.

The exercise demonstrates that Zn, a metal, is more ductile than Si, a metalloid. This aligns with the general trend where metals can be drawn into wires or hammered into sheets, unlike metalloids, which may not sustain such deformations.