Question

Answer the following questions for the elements from cerium through lutetium: (a) Are they metals or nonmetals? (b) To what general class of elements do they belong? (c) What subshell is being filled by electrons in these elements?

Short answer

(a) Metals, (b) Lanthanides, (c) 4f subshell.

Step-by-step solution

Identify the Elements

Cerium through lutetium refers to the elements with atomic numbers 58 (Cerium) to 71 (Lutetium). These elements are part of the lanthanide series and are typically found on the periodic table in the f-block.

Determine if They Are Metals or Nonmetals

The lanthanides, including elements cerium through lutetium, are all metals. They are known as rare-earth metals and have metallic properties such as high electrical conductivity and luster.

Classify the Elements

These elements belong to the class of elements known as the "lanthanides". The lanthanides, along with the actinides, make up the f-block of the periodic table and are often considered as inner transition metals.

Identify the Subshell Being Filled

For the lanthanides from cerium to lutetium, the 4f subshell is being progressively filled. Each successive element adds an additional electron to the 4f subshell, which is characteristic of this series.

Key concepts

Rare-earth metals

The lanthanides, which include elements from cerium to lutetium, are known as rare-earth metals. Despite their name, these metals are actually quite abundant in the Earth's crust but are typically dispersed which makes extracting them economically challenging. Rare-earth metals are renowned for specific characteristics:

• High electrical conductivity: These metals are excellent conductors of electricity, making them valuable in various electronic applications.
• Lustrous appearance: They possess a shiny finish, similar to other metals, making them appealing for manufacturing and decorative purposes.
• Magnetic properties: Some rare-earth elements are exceptionally magnetic, which has led to their use in high-performance magnets.

Rare-earth metals play a crucial role in modern technology, ranging from smartphone components to green technology solutions such as wind turbines and electric vehicle batteries.

Inner transition metals

Inner transition metals are elements that belong to the f-block of the periodic table, composed of the lanthanides and actinides. The lanthanides, including cerium through lutetium, are an important part of this category. The term 'inner transition metals' reflects their position in the periodic table, where they are placed between the transition metals and main group elements.

Inner transition metals display some unique characteristics:

• Variable oxidation states: These metals can exhibit multiple oxidation states, typically making them versatile in chemical reactions.
• Complex formation: They often form complex compounds with various ligands, which plays a significant role in catalysis and industrial chemistry.
• High melting and boiling points: Generally, these metals withstand high temperatures before melting or boiling, which is favorable for their use in high-temperature processes.

These properties make inner transition metals indispensable in many technological advances and industrial processes.

4f subshell

The 4f subshell is a crucial component of the lanthanide series. As electrons fill the 4f subshell, the properties of the elements from cerium to lutetium are defined. The 4f subshell can hold up to 14 electrons, and its filling gives rise to unique physical and chemical characteristics within this series.

Key points about the 4f subshell in lanthanides include:

• Progressive filling: Starting from cerium, each element adds an additional electron to the 4f subshell until it is fully filled by the time we reach lutetium.
• Shielding effect: The electrons in the 4f subshell are "shielded" by outer electrons, which somewhat affects the chemical reactivity and ionic radii of these elements.
• Colorful compounds: Many lanthanides can form compounds that are colorful, attributed to electronic transitions involving 4f electrons.

Understanding the filling of the 4f subshell is essential for grasping the chemistry and physics of lanthanides.