All matter is made of elements, substances that cannot be broken down by chemical activity; in other words, substances that cannot be reduced to any simpler substance by normal physical forces.
An atom is the smallest particle of an element that retains the properties of the elements. Atoms are the building blocks for everything in the universe including ourselves.
People often think of atoms as the smallest possible forms of matter but even smaller particles make up atoms, such as protons, neutrons, and electrons.
Any object that occupies space and has weight is called matter.
Matter is always found in three states: solid, liquid, and gas.
Matter is made of millions of tiny particles called atoms.
Whether solid, liquid, or gas, an atom forms the basic unit.
Atom comes from the Greek word atomos, meaning indivisible.
Two or more atoms combine to give rise to a molecule.
A molecule can be two atoms of the same element or a combination of different elements.