Question

what defines a pure substance?
a combination of various elements and compounds mixed together.
a substance made of the same type of atom, such as elements on the periodic table.
a mixture of ingredients that are not evenly mixed throughout.
a new substance formed by chemically bonding two or more mixtures.

Explanation:

A pure substance is either an element (made of the same type of atom) or a compound (made of molecules with a fixed ratio of atoms). Option A describes a mixture. Option C describes a heterogeneous mixture. Option D is incorrect as mixtures are not chemically bonded to form a new substance. Option B correctly describes an element (a type of pure substance) as a substance made of the same type of atom.

Answer:

B. A substance made of the same type of atom, such as elements on the Periodic Table.