Which statement best describes the relationship between compounds and elements?

• A. Elements are formed by the decomposition of compounds.
• B. Compounds are substances formed by the chemical combination of two or more different elements in fixed proportions.
• C. Compounds and elements have identical chemical properties.
• D. Compounds are mixtures of elements that can be separated by physical means.

Answer: (B)

Verified step by step guidance

1. Understand the definitions of elements and compounds: Elements are pure substances consisting of only one type of atom, while compounds are substances formed when two or more different elements chemically combine in fixed ratios.
2. Recognize that compounds have different chemical properties from the elements that compose them because chemical bonding changes the nature of the substance.
3. Recall that compounds cannot be separated into their elements by physical means; instead, chemical reactions are required to break the bonds between elements.
4. Note that elements are not formed by decomposing compounds; rather, compounds are formed from elements through chemical reactions.
5. Conclude that the best description is that compounds are substances formed by the chemical combination of two or more different elements in fixed proportions.