Which statement about atoms in matter is true?

Which statement about atoms in matter is true?

• A. A t o m s are only found in compounds.
• B. Atoms are the basic units of matter, consisting of protons, neutrons, and electrons; elements are made of one type of atom.
• C. Elements are made of many different atoms.
• D. Atoms are the heaviest part of matter.

Answer: (B)

Atoms are the basic units of matter. Each atom has a tiny nucleus made of protons and neutrons, with electrons orbiting around it. Elements are pure substances made of only one kind of atom, meaning every atom in that element has the same number of protons. There can be variations with different numbers of neutrons (isotopes), but they still belong to the same element. The other statements miss important facts: atoms exist in pure elements as well as in compounds, an element isn’t made of many different atoms, and atoms aren’t the heaviest part of matter. This description best captures how atoms and elements relate.

Atoms are the basic units of matter. Each atom has a tiny nucleus made of protons and neutrons, with electrons orbiting around it. Elements are pure substances made of only one kind of atom, meaning every atom in that element has the same number of protons. There can be variations with different numbers of neutrons (isotopes), but they still belong to the same element. The other statements miss important facts: atoms exist in pure elements as well as in compounds, an element isn’t made of many different atoms, and atoms aren’t the heaviest part of matter. This description best captures how atoms and elements relate.