Why Is Calcium Fluoride,Ca $\mathrm { F } _ { 2 }$

question 11

Multiple Choice

Why is calcium fluoride,Ca $\mathrm { F } _ { 2 }$ ,a high melting point crystalline solid while stannic chloride, $\mathrm { SnCl } _ { 4 }$ ,is a volatile liquid?

• A)There is no theory to predict the physical property of melting point.Melting point temperatures are empirically determined.
• B)Actually,we would predict these results to be the opposite.Since each metal is combined with a group 17 halogen,the heavier metal (tin)combination should have the higher melting point.
• C)Ca \(\mathrm { F } _ { 2 }\) is a small,linear,non-polar molecule,while \(\mathrm { SnCl } _ { 4 }\) is a huge tetrahedral structure.Therefore the bonds in calcium fluoride tend to give it a higher melting point temperature.
• D)Ionic compounds formed by elements on opposite sides of the periodic table,like \(\mathrm { CaF } _ { 2 }\) ,tend to have higher melting points than more covalently bonded structures,like \(\mathrm { SnCl } _ { 4 }\)

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Definitions:

Coxal

Pertaining to the hip or hip joint, often used in the context of bone anatomy to describe the region or aspects of the pelvis.

Fontanel

Soft spots on an infant's skull where the bones have not yet fused, allowing for growth of the brain and skull.

Diaphysis

The shaft or central part of a long bone, which is typically cylindrical in shape and provides leverage and major weight support.

Sinus

A hollow, cavity, or channel within the body, often referring to the air-filled spaces in the skull that open into the nasal cavity.