Understanding Metalloids and Element Classification

Elements on the periodic table can be broadly classified into metals, nonmetals, and metalloids. Metalloids, also known as semimetals, are elements that exhibit properties intermediate between those of metals and nonmetals. They are typically located along the dividing line between metals and nonmetals on the periodic table.

Common Metalloids

The six commonly recognized metalloids are:

• Boron (\( \text{B} \))
• Silicon (\( \text{Si} \))
• Germanium (\( \text{Ge} \))
• Arsenic (\( \text{As} \))
• Antimony (\( \text{Sb} \))
• Tellurium (\( \text{Te} \))

Some sources also include Polonium (\( \text{Po} \)) and Astatine (\( \text{At} \)) as metalloids, though they are often classified as metals or halogens respectively.

Analyzing the Given Options

Let's examine each element provided in the options and determine its classification:

• Xenon (\( \text{Xe} \)): Xenon is a noble gas, located in Group 18 of the periodic table. Noble gases are a type of nonmetal. Xenon is a gas at room temperature, lacks metallic luster, and does not conduct electricity well. Therefore, Xenon is a nonmetal.
• Polonium (\( \text{Po} \)): Polonium is in Group 16. While sometimes considered a metalloid due to exhibiting some properties of both metals and nonmetals, it is more often classified as a metal, specifically a post-transition metal, due to its primarily metallic characteristics (like electrical conductivity). Its classification can sometimes be debated, but it is less definitively a metalloid than Germanium or Tellurium.
• Tellurium (\( \text{Te} \)): Tellurium is in Group 16, below Oxygen and Sulfur. It is widely accepted and consistently classified as a metalloid. It shows semiconducting properties.
• Germanium (\( \text{Ge} \)): Germanium is in Group 14, below Carbon and Silicon. It is consistently classified as a metalloid. It is a well-known semiconductor used in electronics, showcasing its intermediate properties between metals and nonmetals.

Identifying the Non-Metalloid Element

Based on the classifications, Xenon is clearly a nonmetal (a noble gas). Germanium and Tellurium are recognized metalloids. Polonium's classification as a metalloid is less certain than Germanium or Tellurium, often being listed as a metal, but Xenon is definitely not a metalloid; it's a nonmetal.

Therefore, the element that is NOT a metalloid among the given options is Xenon.

Conclusion

Comparing the properties and common classifications, Xenon stands out as a nonmetal, distinctly different from the metalloid properties of Germanium and Tellurium, and even distinct from the sometimes-debated classification of Polonium. The question asks for the element that is NOT a metalloid, and Xenon fits this description as a noble gas (nonmetal).

Revision Table: Element Classification Key Facts

Additional Information: Location on the Periodic Table

The location of elements on the periodic table can help identify their general classification:

• Metals are found predominantly on the left and in the center of the periodic table.
• Nonmetals are generally found on the right side, above the metalloids. This group includes noble gases (Group 18), halogens (Group 17), and other elements in Groups 14-16.
• Metalloids are typically found along the "staircase" line that separates metals from nonmetals, starting from Boron.

Understanding the periodic table trends is crucial for classifying elements.