d and f BLOCK ELEMENTS

How do lanthanoids generally conduct heat and electricity?

• Poor conductors
• Good conductors
• Insulators
• Semiconductors

What type of crystal structure do lanthanoids typically possess?

• Ionic crystal structure
• Covalent network structure
• Metallic structure
• Molecular crystal structure

What is the appearance and general reactivity of lanthanoids when exposed to air?

• Grey and brittle, stable in air
• Shiny black, stable in air
• Silvery white, tarnish rapidly
• Colorless and gaseous, react explosively

What is the typical melting point range for most lanthanoids?

• 500 to 800 K
• 1000 to 1200 K
• 1500 to 1800 K
• Above 2000 K

What is the general trend in the hardness of lanthanoids as atomic number increases?

• Hardness decreases
• Hardness remains constant
• Hardness increases
• Hardness fluctuates randomly