Question

question 2: alex is developing models to explain how matter is classified. what is required in her model of a compound? a the substance is composed of at least two different elements. b the atoms in the substance are held together in chemical bonds. c the particles of the substance do not move freely past each other. d the substance is composed of at least one element that is a metal.

Explanation:

A compound is a substance made up of two or more different elements chemically bonded together. Option A only mentions different elements but not the chemical - bonding aspect. Option C is related to the state of matter rather than the definition of a compound. Option D is too restrictive as a compound doesn't necessarily have to contain a metal. Option B correctly states that atoms in a compound are held together by chemical bonds.

Answer:

B. The atoms in the substance are held together in chemical bonds.