This is an atom.
element
All of the elements of the Periodic Table cannot be broken down into simpler substances.
If an unknown substance cannot be broken down into simpler substances it is made of one kind of atom and an element.
An atom is smallest particle there is and it cannot be broken down any more.
I think your referring to an element, the basic unit(s) that cannot be broken down without fission.
A substance that cannot be broken down (science)
molecule
An element cannot be broken down into a simpler substance by chemical means.
A pure substance that cannot be broken down is an Element.
A substance that cannot be broken down is a pure substance
An element is the only substance that cannot be broken down.
element
an element is a substance that cannot be broken down into a simpler form by chemical means
An Element ... A substance that cannot be broken down into simpler substances by chemical means.
T=It is true that compounds is a type of substance. This substance cannot be broken down.
All of the elements of the Periodic Table cannot be broken down into simpler substances.
No. Elements cannot be broken down into simpler substances in a chemical reaction.
No, it can be broken down.