What is an element?

This article gives an explanation of what an element is by discussing the structure of atoms of an element. All the atoms of an element have the same number of protons and the same number of electrons in the nucleus, but many have different numbers of neutrons in the nucleus. It is important to understand what an element is in order to master the subject of chemistry.

Definition
An element can be defined as a substance that is made up from only one type of atom. All of the atoms in an element are the same; this means that each atom contains the same number of protons. For example, hydrogen atoms all contain one proton. Oxygen atoms all contain eight protons and carbon atoms all contain six protons. Keeping a record of elements Elements are recorded in the modern periodic table. They are listed in order of their atomic number, which is also called the proton number. This is the number which tells us how many protons are found in the nucleus. This number also tells us how many electrons an atom has, as the number of positively charged protons is the same as the number of negatively charged electrons. Overall, the atom has a neutral charge. Atoms of the same element may have different numbers of neutrons - these are called isotopes. For example, oxygen has two naturally occurring isotopes; Oxygen-16 (which has 8 neutrons) and Oxygen-18 (which has 10 neutrons). The facts At the time of writing, there are 114 confirmed elements by the IUPAC (Iupac.org). 22 of the elements on the periodic table are non-metals while the remainder are metallic elements. Every element has its own chemical symbol; these are displayed on the periodic table along with the atomic mass and atomic number of each element. Every symbol consists of an upper case letter, Hydrogen has the symbol H. A symbol may sometimes include an upper and lower case letter. Helium, for example, has the symbol He.