What is a substance that contains only one type of atom called?

What do you call a combination of two or more substances that are not chemically bonded together?

What term describes a material made up of two or more different elements that are chemically combined?

What do you call a substance that has a definite and uniform composition, without any variation?

What is a one or two-letter abbreviation used to represent an element called?

What is the representation of the types and numbers of atoms in a compound called?

What do you call a kind of matter that can be separated into its components by physical processes?

What is the smallest unit of matter that retains the properties of an element called?

What term is used to describe a mixture that is not uniform throughout, where different components can be easily distinguished?