Here's why:

* Elements are the simplest pure substances. They cannot be broken down into simpler substances by chemical means.

* Atoms are the smallest unit of an element that retains the chemical properties of that element.

Think of it like this: Imagine building blocks. Each type of building block represents a different element. You can build various structures using different combinations of building blocks, but each individual building block is always the same.

For example:

* Gold is an element, and it is made up of only gold atoms.

* Oxygen is an element, and it is made up of only oxygen atoms.

It's important to distinguish this from compounds, which are formed when two or more different elements combine chemically. Water (H₂O) is a compound because it is made of two hydrogen atoms and one oxygen atom.