What is the basic unit of matter?

• A. Atom
• B. Molecule
• C. Cell
• D. Ion

Answer: (A)

The basic unit of matter is the atom. Everything around us is built from atoms, and an atom retains the properties of the element it represents. Atoms can join with other atoms to form molecules, which are the actual building blocks of most substances you encounter. An atom has a dense nucleus of protons and neutrons, with electrons orbiting around it; the way these subatomic parts are arranged governs how the atom bonds and interacts with others. If an atom gains or loses electrons, it becomes an ion, which is still an atom but with a charge. A molecule is made of two or more atoms bonded together, like water being two hydrogen atoms bonded to one oxygen atom. A cell is the basic unit of life and contains many atoms and molecules, but it’s not the smallest unit of matter itself.