Two substances with crystal structures can be different even if the substances contain the same chemical elements in the same ratio. These substances have the same composition, but they are different because their atoms are arranged in different ways.

Question

Select the two models that represent substances with the same chemical formula but different arrangements of atoms.

C

Si

Answer 1

It seems like you're referring to two different crystal structures of the same chemical elements, which is a classic illustration of polymorphism. In your case, you mentioned silicon (Si), which can exist in different forms.

The two common allotropes of silicon are:

1. Diamond cubic (Diamond structure): This is a well-known structure of silicon where each silicon atom is tetrahedrally coordinated with four other silicon atoms.

2. Cubic silicon (Si): This refers to the more common crystalline form of silicon found in electronic devices, which shares a similar diamond structure but follows a slightly different arrangement when considering impurities and defects.

If your options are referring to models representing these structures, you would likely look for one indicating the diamond structure and another that shows a more complex or different cubic arrangement.

If you have specific images or diagrams that represent these structures, please provide details so I can assist you better in choosing the correct models.