Types of atoms. the basic unit of matter. pure substance is what?

Solids, liquids, gases, and plasma are all matter. When all atoms that make up a substance are the same, then that substance is an element. Elements made of only one kind of atom. Because of this, elements are called "pure" substances.

hope this helps :)

A pure substance is a substance that doesnt have any additional ions added to it

For example, in bottled water there are Magnesium ions in it along with others. This is NOT PURE WATER

Also pure substances can be retrieved using separating techniques

since electrons are negative the answer is neagtaive

what is the question here. i think you messed up.