What does a Gram Negative stain show? - Stains the background of bacteria - The dye does not stick to the specimen, instead settles around its boundaries, creating a silhouette
A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z. The mass number is the sum of the number of protons and neutrons in a nucleus.
Science for Youth May 16, 2011. A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. When a compound is formed from its components, a chemical change takes place through chemical reactions.