Chemical Formulae

An element is a simple chemical made up of only one type of atom. Pure gold is an element because it contains gold atoms only. 

As there are 92 kinds of naturally occuring atoms, so there are 92 naturally occurring elements in the universe. 

An element cannot be broken down into simpler substances. Water can be broken down into hydrogen and oxygen gases, so it is not an element. Liquid mercury cannot be broken down into simpler substances, so it is an element. 

Most of the elements are solids. Eleven are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neone, chlorine etc.) and just two are liquids (mercury and bromine). 

Most of the elements are metals. 

Only 20 or so are non-metals. 

Each element has been given a distinct name. Often the name was given to the element by the scientist who discovered the element.
Each symbol also has a chemical symbol - a letter code for the element. For example, C is the code for carbon, N for nitrogen, and S for sulfur. 

Some elements have single-letter codes, but most have two-letter codes, e.g. Mg for magnesium. 

Most symbols are derived from the element's English name, but a few come from the element's name in another language.