Element

A chemical element is a species of atom having the same number of protons in their atomic nuclei.

Trace Element

A trace element is a chemical element whose concentration is very low.

Compound

A chemical compound is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds

Chemical Reaction

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.

Reactant

a substance that takes part in and undergoes change during a reaction.

Product

Products are the species formed from chemical reactions. During a chemical reaction reactants are transformed into products after passing through a high energy transition state.

Molecule

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.

Macromolecule

a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer.

Carbohydrate

any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose