Which of the following best describes two ways that compounds differ from the elements that form them?

• A. Compounds always have the same physical properties as their constituent elements but different chemical properties.
• B. Compounds have different chemical properties and different physical properties compared to their constituent elements.
• C. Compounds are mixtures of elements and retain the properties of those elements.
• D. Compounds can be separated into elements by physical means and have identical chemical properties to those elements.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the difference between elements and compounds. Elements are pure substances consisting of only one type of atom, while compounds are substances formed when two or more elements chemically combine in fixed ratios.
2. Step 2: Recognize that compounds have unique chemical properties that are different from the properties of the individual elements that compose them. This is because the atoms are bonded together, creating new substances with new behaviors.
3. Step 3: Note that compounds also have different physical properties (such as melting point, boiling point, color, and density) compared to their constituent elements, due to the new arrangement and bonding of atoms.
4. Step 4: Understand that compounds cannot be separated into their elements by physical means (like filtration or distillation); instead, they require chemical reactions to break the bonds between atoms.
5. Step 5: Conclude that the best description is that compounds have both different chemical and physical properties compared to the elements that form them, distinguishing them clearly from mixtures or simple combinations of elements.