What Is An Element In Chemistry?

by Kate Onissiphorou

An element in chemistry refers to the simplest chemical form in which a substance can exist. Put simply, it means it can’t be further broken down or decomposed into simpler chemical substances.

Knowing how many protons (the atomic number) are in each element makes it possible for scientists to organise elements in a periodic table. The arrangement of the periodic table reveals certain patterns based on elements’ properties, which enables us to reasonably predict or model various chemical reactions and configurations.

Read on to learn more about the different types of elements in chemistry and five key examples.

Elements in chemistry explained

In chemistry, elements are considered the most fundamental substances because they can’t be decomposed into simpler substances. They’re identified by the number of protons they have in their atomic nucleus. Summary of the periodic table

Elements have periodicity and groupings that exhibit certain patterns, trends, and characteristics. You can refer to the modern periodic table of chemical elements to determine certain properties of the elements. 

For example, the elements belonging to Group 18 (VIIIa) are classed as noble gases, which are virtually inert. As you move diagonally across the periodic table in the main sequence, the metallic properties of the elements increase.

Of the 118 known elements in the periodic table, 92 occur naturally. Those with atomic numbers 93 to 118 are highly unstable artificial elements that have been created in nuclear reactors. It’s worth noting that both technetium (Tc) and promethium (Pm) were also formed in nuclear reactors but their atomic numbers are 43 and 61 respectively.

Promethium and technetium are special case elements as they don’t have stable isotopes. Promethium can’t be found on the earth’s crust. In fact, there’s only one known star in the Andromeda galaxy that produces this element naturally, although the mechanism is still unknown. Meanwhile, technetium occurs naturally as the fission product in uranium and thorium ores.

What are the four types of elements?

Before chemistry became a proper scientific discipline in the 1700s, the study of chemicals was riddled with superstition and magical beliefs. Before the Age of Enlightenment, which gave birth to formal scientific thinking, alchemy reigned supreme in the study of chemicals and chemical reactions.

The four elements: earth, air, water, fire
The Ancient Greeks believed that the four elements of earth, air, water, and fire made up all matter.

Although ancient alchemists discovered many chemical elements and compounds as we know them today, they mistakenly identified air, water, earth, and fire as the four fundamental elements of nature. In modern chemistry, however, we know that:

  • Air is actually a mixture of gases (mainly nitrogen and oxygen)
  • Water is a compound that contains hydrogen and oxygen
  • The earth is in fact a mixture of minerals, organic materials, water, and other solid substances
  • Fire is an ongoing chemical reaction called combustion, which is the exothermic reaction of oxygen with a combustible substance, such as gasoline

In the modern scientific sense, elements can still be classified into four types based on their state of matter. Hence, an element can be a gas, liquid, solid, or plasma. However, it’s more accurate to classify elements in the periodic table according to their general chemical properties:

  1. Metals – these elements have a strong tendency to donate or lose their electrons. Examples include sodium, magnesium, aluminium, and iron.
  2. Non-metals – these elements tend to accept electrons. Oxygen, sulphur, chlorine, and fluorine are just some examples of non-metal elements.
  3. Metalloids – often acting as semiconductors, these elements have properties in between metals and nonmetals. Examples include silicon, germanium, arsenic, and antimony.
  4. Noble gases – these are inert or unreactive gases because they have fully-filled electronic configurations. Helium, neon, and xenon are all examples of noble gases.

What is a pure element in chemistry?

In nature, it’s virtually impossible to find an element in its pure (100%) form. Most are reactive and combine with other elements to form compounds, while others exist in ores that are mixed with other elements and minerals. Even noble gases can’t be found in a completely pure form in nature. 

That being said, it is possible to extract and purify these elements. Hence, a pure element in chemistry refers to a substance that contains only one type of atom without any impurities.

Examples of elements in chemistry

The modern periodic table contains 118 elements, but only 92 of those are naturally occurring. The remaining elements are created by artificial means, such as in particle accelerators or nuclear reactions. These types of elements are highly unstable and easily decay into lighter elements.

Here are five important examples of elements:

  1. Hydrogen (atomic number 1) – hydrogen is the most abundant element in the universe. It’s mainly found in interstellar clouds and stars as fuel for fusion reactions. It’s also the simplest of all the elements. Deep space, with a star field background
  2. Chlorine (atomic number 17) – chlorine is a strong oxidising agent that occurs naturally as a component of sodium chloride and other compounds.
  3. Zinc (atomic number 30) – this is a common metal used in batteries and as a galvanic coating for iron.
  4. Phosphorus (atomic number 15) – phosphorus plays an important biological role and is essential for building strong bones and teeth. It’s also important in the synthesis of protein and adenosine triphosphate, or ATP.
  5. Molybdenum (atomic number 42) – a cofactor of enzymes such as mitochondrial amidoxime reducing component (mARC), molybdenum also has a crucial role in biology.


An element in chemistry refers to a fundamental substance that can’t be further broken down or decomposed into simpler substances using chemical processes. Elements can be identified by the number of protons in the nucleus of an atom. They can then be arranged in the periodic table in a way that reveals their general trends, patterns, and characteristics.


The blog on chemicals.co.uk and everything published on it is provided as an information resource only. The blog, its authors and affiliates accept no responsibility for any accident, injury or damage caused in part or directly from following the information provided on this website. We do not recommend using any chemical without first consulting the Material Safety Data Sheet which can be obtained from the manufacturer and following the safety advice and precautions on the product label. If you are in any doubt about health and safety issues please consult the Health & Safety Executive (HSE).