Question

Choose the more metallic element from each pair. (a) Sb or Pb (b) Kor Ge (c) Ge or Sb (d) As or \(\mathrm{Sn}\)

Short answer

The more metallic element in each pair is: (a) Pb, (b) K, (c) Ge, (d) Sn.

Step-by-step solution

Identifying the Position in the Periodic Table

To determine which element is more metallic, look for the position of the elements in the periodic table. Elements that are to the left and lower on the periodic table exhibit more metallic character.

Comparison of Sb and Pb

Antimony (Sb) is located in group 15 and period 5 while Lead (Pb) is in group 14 and period 6. Since Pb is lower on the periodic table than Sb, Pb is more metallic.

Comparison of K and Ge

Potassium (K) is in group 1 and period 4, and Germanium (Ge) is in group 14 and period 4. K is to the left of Ge on the periodic table, which makes K more metallic.

Comparison of Ge and Sb

Both Ge and Sb are in period 5, but Ge is in group 14 while Sb is in group 15. Ge is to the left of Sb, therefore Ge is more metallic.

Comparison of As and Sn

Arsenic (As) is located in group 15 and period 4, whereas Tin (Sn) is in group 14 and period 5. Sn is lower in the periodic table than As, making Sn more metallic.

Key concepts

Periodic Table Trends

Understanding the periodic table is crucial for studying the fundamental concepts of chemistry. One of the most significant trends in the periodic table is the variation in metallic character of elements. As you go across a period from left to right, elements become less metallic and more nonmetallic. This is due to the increase in nuclear charge, which attracts the electrons more strongly and decreases the tendency to lose electrons, a characteristic of metals.

On the other hand, as you move down a group, elements become more metallic. This can be attributed to the additional electron shells that increase the distance between the outermost electrons and the nucleus. This enlargement reduces the nuclear attraction on the outer electrons, making them more easily lost in chemical reactions, which is a metal trait. Thus, metallic character decreases across a period and increases down a group in the periodic table.

Metallic vs Nonmetallic Elements

Metallic and nonmetallic elements exhibit distinct properties and behave differently in chemical reactions. Metals tend to lose electrons to form positive ions and are good conductors of heat and electricity. They are often malleable, ductile, and possess a shiny luster. Nonmetals, in contrast, are more likely to gain electrons to form negative ions, are poor conductors of heat and electricity, and are not reflective like metals.

Characteristic Properties of Metals:

• High electrical and thermal conductivity
• Malleability and ductility
• Shiny surface (luster)
• Tendency to form cations

Characteristic Properties of Nonmetals:

• Poor conductors of heat and electricity
• Brittle in solid form
• Lack of luster
• Tendency to form anions

In a chemical context, these differences are fundamental for predicting the type of compounds that elements will form, whether ionic or covalent.

Group and Period Comparison

When comparing the metallic character of elements, it is essential to consider their position in a group and a period. In the previously solved exercise, students compared elements within the same period and group to evaluate their metallic character. As noticed, elements in the lower groups and periods are generally more metallic due to their position in the periodic table.

For elements within the same period, the element toward the left is more metallic because it has fewer valence electrons and less attraction from the nucleus, making electron loss more likely. For elements within the same group, the element that is lower down has more electron shells and the valence electrons are further away from the nucleus, which makes them more metallic as they can lose electrons more readily. This trend is crucial for understanding reactivity and bonding behaviors in various chemical elements.