Which statement best describes an element?

Which statement best describes an element?

• A. A pure substance made of only one kind of atom
• B. A substance made from two or more elements chemically bonded
• C. A substance that can be separated into simpler substances by physical means
• D. A mixture of different elements

Answer: (A)

An element is a pure substance that contains only one kind of atom. All the particles are the same type of atom, even if those atoms pair up to form molecules like O2 or N2. Because it’s only one kind of atom, it cannot be broken down into simpler substances by chemical means. The other descriptions point to substances that are not elements: two different elements bonded together form a compound; a substance that can be separated into simpler substances by physical means is a mixture; and a mixture of different elements is also a mixture. So the description that fits an element is a pure substance made of only one kind of atom.

An element is a pure substance that contains only one kind of atom. All the particles are the same type of atom, even if those atoms pair up to form molecules like O2 or N2. Because it’s only one kind of atom, it cannot be broken down into simpler substances by chemical means. The other descriptions point to substances that are not elements: two different elements bonded together form a compound; a substance that can be separated into simpler substances by physical means is a mixture; and a mixture of different elements is also a mixture. So the description that fits an element is a pure substance made of only one kind of atom.