Pure substances that cannot be separated into simpler substances are called elements.

Here's a breakdown:

* Pure Substance: A substance made up of only one type of particle.

* Element: A pure substance that cannot be broken down into simpler substances by chemical means. They are the fundamental building blocks of all matter.

Examples of Elements:

* Oxygen (O)

* Hydrogen (H)

* Carbon (C)

* Gold (Au)

* Iron (Fe)

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