Final answer:
An element cannot be separated into smaller materials except during nuclear reactions. Elements are made of atoms, the smallest units participating in chemical reactions, and there are 118 recognized elements that cannot be broken down into simpler components by chemical means.
Step-by-step explanation:
An element cannot be separated into smaller materials by ordinary physical or chemical means. However, during nuclear reactions, which are not considered ordinary chemical processes, an element can indeed be altered and broken down into subatomic particles such as protons, neutrons, and electrons. Hence, the correct answer is: b) An element cannot be separated into smaller materials except during nuclear reactions.
Elements are pure substances that are made up of atoms, and the atoms are the smallest units that participate in chemical reactions. While an atom itself can be broken down into subatomic particles such as protons, neutrons, and electrons, it is the smallest particle that takes part in chemical processes that define an element. Compounds, on the other hand, are substances that can be chemically broken down because they are composed of two or more elements.
Close to 90 naturally occurring elements are known on Earth, and scientists have created almost 30 additional elements. Overall, including both naturally occurring and synthesized, there are 118 recognized elements that form the basis of countless compounds. It's crucial to note that while compounds and mixtures can be broken down into simpler components, elements, by definition, cannot. They are the building blocks of all matter.