Final answer:
A naturally occurring piece of silver is the material not composed of different types of atoms, as silver is an element consisting solely of silver atoms. Air is a homogeneous mixture, synthetic plastics are compounds or mixtures, and metal alloys are homogeneous mixtures of two or more metallic elements.
Step-by-step explanation:
The material that is not composed of different types of atoms among the choices provided is a naturally occurring piece of silver. Silver (Ag) is an element, which means it is made up solely of silver atoms and does not combine different types of atoms within its structure. The other options, such as a sample of air on Earth, a synthetic plastic, and a metal alloy, are all composed of different types of atoms. Air is a homogeneous mixture of gases, synthetic plastic is typically a compound or mixture of compounds, and a metal alloy is a homogeneous mixture consisting of two or more elements, typically metals, that are mixed at the molecular level.
Examples to further clarify these classifications:
- Salt (sodium chloride) is a compound containing two different elements, sodium and chlorine.
- Pure water is also a compound made of hydrogen and oxygen.
- Soil is an example of a heterogeneous mixture as it contains a variety of different materials that are not uniform throughout.
- Salt water (sea water) is a homogeneous mixture because the salt is evenly distributed throughout the water.
- Pure air is typically considered a homogeneous mixture of different gases.
- Carbon dioxide is a compound consisting of carbon and oxygen.
- Gold in its pure form is an element.
- Bronze is a metal alloy, hence a homogeneous mixture of copper and other metals such as tin.